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Nickels, dimes, and quarters 2018-04-20
From Patti:
A copy machine accepts nickels, dimes, and quarters. After 1 hour, there are 30 coins total, and their value is \$5.10. How many nickels, quarters, and dimes are in the machine? (Hint: There are exactly five different solutions.)
Peanuts in 5 bags 2017-09-17
From Maria:
There are a total of 270 peanuts divided up into five different bags. The first two bags contain 174 peanuts between the two of them. The second and third bags contain 130 peanuts between the two of them. The third and fourth bags contain 86 peanuts between the two of them. The fourth and fifth bags contain 42 peanuts between the two of them. How many peanuts are in each bag?
A puzzle with some integers 2017-03-30
From Glen:
Use 7,7,5,5 to equal 3 only using each # once and each math function once
How much does the fish weigh? 2017-03-08
From Jeri:
Fish is caught that weighs 5 pounds plus half its weight. How much does the fish weigh?
20/2 + 2 * 2^2 + 6 = 8 2016-09-15
From Simone:
20/2 + 2 * 2^2 + 6 = 8

insert brackets to make this true

A puzzle embedded in a table top 2016-05-13
From Aaron:
I want to make a table with a puzzle embedded in it. The table top would be a 36" circle and the puzzle is 20"x27" I'm thinking that it's not going to fit, but not sure. Any help would be appreciated.
Thanks,
Aaron

A problem with numbers 2014-05-14
From Justina:
Okay so I don't understand how to equal this equation to 10 using bedmas. I've been stuck on it for a few days now. Is there different ways you can show me Using these same numbers?

5 2 4 3 1 = 10

Help! Thanks.

Answered by Robert Dawson and Penny Nom.
Every vertex of a cube is assigned a number +1 or -1 2013-04-01
From Shankar:
Every vertex of a cube is assigned a number +1 or -1 . Every face has a number that is the product of all the numbers in its corners. Then the 14 numbers are summed up ( all the vertices and faces ). Can the sum be 0?
A 3 digit number puzzle 2013-03-11
From Bonnie:
My number has 3 digits. My number is not a multiple of 100. My number is a multiple of 50. My number is a factor of 1000. What is my number?
100 animals 2013-02-25
From Jessica:
You have exactly \$100.00 to spend. You must get 100 animals.
The chicks cost \$0.10 each.
The pigs cost \$2.00 each.
The sheep cost \$5.00 each.
You must get some of each animal.
How many of each animal can you get?

Use 9,10,6,8, and 4 to make 10 2013-01-25
From Able:
How do you calculate using BEDMAS 9,10,6,8,4 to equal 10
A balance puzzle 2013-01-14
From Emily:
I'm stuck on this problem and feel that it can't work! The problem is: there is a door with a balance scale on it. In order to open the door, you have to use the 5 weights to balance the scale. On the left side you have 2 boxes to place the weights and on the right side you have 3. You're 5 weights are as follows: 1lbs, 2lbs, 3lbs, 4lbs, 5lbs. How do you place the weights so that the scale is balanced?
A puzzle with a triangle and 57 2012-04-25
From sharon:

Question from sharon, a parent:

We have been battling with this for days and cant find any solution -

Using each of the following numbers once, fill all the spaces in the triangles so that each side of the triangle adds up to 57

numbers are 11,12,13,14,15,16,17,18,19

diagram is -

 0 0 0 0 57 0 0 0 0 0

Any ideas ? this has to be in in just over 24 hrs ......help!

A number puzzle 2012-04-07
From Kenya:
my number is less than 25
my number of tiles will make only one rectangle
my number is odd
my number is a factor of 36

Can the result of the calculation be 2? 2012-02-09
From Thomas:
You have the digits 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9 in a random order side by side and put randomly between two digits a colon, so that a division comes into existence. Can the result of the calculation be 2?
Answered by Robert Dawson and Chris Fisher.
Today is Emma's Birthday. 2012-01-25
From Mike:
Today is Emma's Birthday.
Emma's mother is four times as old as Emma is today.
In four years, Emma's mother will be three times as old as Emma.
How old is Emma today?

A problem in logic 2012-01-19
The puzzle below I know the answer to; because someone told me! My question is: how could I answer it using logic, maths, etc. what field of inquiry does this kind of problem fall into? Puzzle: You are in a room with two men: one is a compulsive liar and the other is a compulsive honest. There are two doors: one leading to heaven, the other to hell. The two men know which door leads to where. You want to go to heaven but are allowed only ONE question from one or the other of the two men. What would that question be? [The question to ask, from either man, is: "if I asked the OTHER man which door leads to heaven, which door would he point?". You would then choose the other door.] Has this answer got any basis in logic or maths at all?
15 pigs and 6 pens 2011-11-16
From Mike:
I have 15 pigs and 6 pens, I have to put them in odd numbers, how do I do it.
A word puzzle 2011-11-10
From kevin:
ABCD
ABCD
ABCD
ABCD
-------
EBEA

What does each letter stand for? I've been at it for days and still have nothing.
Thank you,
Kevin

Ben's favourite numbers 2011-08-03
From Luke:
Ben challenges you to guess his favourite numbers by using the following three clues: -Each number is a four-digit odd number. -Each is a palindrome -The digits of each number add up to 10 -None of the numbers are divisible by 5
How many cats are needed to catch 60 rats in 1 hour? 2011-04-19
From Melody:
If 3 cats can catch 3 rats in 3 minutes, how many cats are needed to catch 60 rats in 1 hour?
Ramon has 6 puppies 2011-04-17
From Mary:
Ramon has 6 puppies. Five of the 6 weigh the same and one puppy is heavier. If Ramon had a balance scale, what is the least number of times he could weigh the puppies to be sure he could determine which puppy was heavier?
2x = 2+2x 2011-01-15
From james:
2x=2+2x can you help me find what x epauls?
Draw a figure with 16 triangles using only 6 line segements 2010-12-16
From Jill:
How can you draw a figure with 16 triangles using only 6 line segements?
A product of 1 000 000 2010-11-19
From Sharron:
There are many pairs of numbers that when multiplied together give a product of 1 000 000. However, there is one pair, and only one pair, of whole numbers that contain no zero digits and has a product of 1 000 000. What are these two numbers?
What numbers can I be? 2010-11-13
From john:
my thousands digit is 2 times my ones digit.my hundreds digit is my ones digit plus 2. my tens digit is the difference between my thousands and hundreds digit what numbers can i be?
Bbippities, bops, and boos 2010-11-05
From Stacey:
six bippities equal three bops,and six bops equal two boos. How many boos are there in one bippity,one bop, and one boo??
39-4+6 divided by 3 to the power of 2 = 3 2010-11-02
From Emma:
Help me and my family cannot figure this out, it the last question on my paper. I need to know how to use place the brackets to make the following problem true.

39-4+6 divided by 3 to the power of 2 = 3

we have tried for three days and cannot get it.......help!

Answered by Robert Dawson and Claude Tardif.
Six nines 2010-09-16
From Steph:
It's sort of one question. We have to use six nines to get the numbers 1-30. I got all but 22, 23, 24, and 30. Like 15 is 9+9-(9+9+9)/9.
Choose any three digits that are less than ten 2010-09-12
From cecille:
my son have a homework, but i don't understand the question. here's the problem:
choose any three digits that are less than ten.
make all the two digit number you can using those three digits.
add up the two digit numbers you created and divided by the sum of the original three digits.

There are 12 balls and one balls weight is different than the others 2010-08-12
From david:
if there was 12 balls and one balls weight is different than the other and use a balance 3 times is there a possible way to find which weigh different
777777 times 111111 2010-07-07
From Chew:
What is 777777 times 111111 without using a calculator?
A table of values 2010-04-22
From Donna:
Complete the table by determining the value of each letter. Explain what rule is used to relate the numbers in the second column (with the heading of y) with those in the first column (with the heading of x).

x | y
3 | 5
9 | 23
4 | 8
6 | A
7 | B
C | 11
D | 2

I can't figure this out, can you help me?

2+3 =10 and 7+2=63 and ... 2010-03-01
From brenda:
if 2+3 =10 and 7+2=63 and 6+5 =66 and 8 +4 = 96 then 9+7+ ??????
its driving me crazy !!

Answered by Penny Nom, Claude tardif and Melanie Tyrer.
Dividing between between two charities 2010-02-22
From Latoya:
a 149,000 estate is to be divided between two charities so that one charity receives 18,000 less than the other. How much will each charity receive?
The game of 24 2010-02-20
From haley:
hello.... we have these very hard make 24 stumpers. i am stuck on one.... how can you make 24 using the numbers 7-7-13-18?? thanks!
7 odd numbers 2010-02-19
From mike:
Hello there, Problem: find 7 odd numbers who sum is equal to 30. Hint*My professor said it's possible to add 7 odd numbers and get 30 for an answer! and he said we can use Negative and rational numbers but no decimal or fractions. So is there anyway of solving this? Please get back to ASAP! thanks.
Answered by Harley Weston and Tyler Wood.
A magic square 2010-02-18
From Mika:
place the integers from -5 to +10 in the magic square so that the total of each row, column, and diagonal is 10.
A magic/math trick 2009-12-04
From Valentin:
What is the explanation for the following math trick: you think of any four digit number add those digits take that sum and subtract it from the first number then you say three of those new numbers in any order and the other person guesses the last digit. How does he do it?
Four fours 2009-11-29
From linda:
Four Fours order of operations challenge i need problems using 4's only that have an answer of 13, 18, and 19 than you
A place value problem 2009-11-29
From Ivy:
My tens digit is 4 less than my thousands digit. My ones digit is twice my tens digit. My ten thousands digit is one less than my ones digit. My hundreds digit is the sum of my tens and thousands digit. My thousands digit is 6.
A number puzzle 2009-11-03
From Jacqui:
Write a number sentence. Use every digit once, 7, 4, 3, 6, 5,10. Insert math symbols +, - , *,/ and end up with the number 3. Use parentheses if necessary.

Jacqui

Answered by Claude Tardif and Penny Nom.
Where is the Father? 2009-10-30
From Jeffrey:
A mother is 21 years older than her kid and within 6 years the child will be 5 times younger than the mother. Where is the Father? Jeffrey
Answered by Robert Dawson and Claude Tardif.
A number between 48 and 59 2009-10-07
From nakia:
I am a number less 59 but greater than 48. my ones digit is 2 more than my tens digit.What's the number?
In what order are the following digits? 2009-09-30
From Jewell:
In what order are the following digits? 0,2,3,6,7,1,9,4,5,8
Answered by Penny Nom and Claude Tardif.
Seven circles 2009-09-20
From Bobbi:
try to put number 1 to 7 in seven circles (one in the middle, 3 on top, 3 below) so the numbers in each row of three circles--vertical, horizontal, and diagonal -- add up to 12. Each number can be used only once.
What is my number? 2009-09-18
From Hanna:
What is my number?
My number is a perfect square.
The only number in its prime factorization is 2.
My number is a factor of 32.
The sum of its digits is odd.

A four-digit positive integer 2009-09-04
From TRACEY:
I AM A FOUR-DIGIT POSITIVE INTEGER SUCH THAT THE SUM OF MY DIGITS IS 18 AND MY DIGITS REVERSED ARE EXACTLY FOUR TIMES GREATER THAN MYSELF. WHAT NUMBER AM I?
A number puzzle 2009-08-28
From Angela:
Taking 1 through 9 and using them only once subtract them to equal 33333
The game of 24 2009-08-26
From melvi:
how can you get the numbner 24 but only useing the numbers 7,5,4,5
Number of Farm Animals 2009-07-06
From paul:
In the farm there are 50 heads of chicken and pigs and 100 feet. how many chickens and pigs are there in the farm
You have the numbers 1 through 8, ... 2009-06-15
From Maryland:
You have the numbers 1 through 8, you can only use each number one time. Two of the numbers are multiplied together, two are subtracted, two more are subtracted and the last two are subtracted. All the answers are the same.
Can't get it, I have racked my brain trying to help.

Number & Operation Puzzle 2009-06-12
From Francine:
How can I get the number 26 using 1,2,3,4,&5 and using addition, subtraction, multiplication and division. Each operator and digit must be used exactly once. My son presented me this question and I can't determine if it's even possible.
A number puzzle 2009-06-10
From Ann:
Hey,
I have a math problem that I can't solve which just happens to be a "must-answer". The answer to the first problem is 25,452 and the second is 21,232. I know how to add but my teacher said that there is a pattern wherein you just have to look at the set of numbers and you already know the answer without really adding it first.  Here are the condition of the problem:
1) the first, second and fourth numbers were provided by me. ( I have no idea how this works)
2) the third and the fifth numbers were given by the teacher. ( She's the one who knows the technique)

# She says that there is a "pattern."
Help me please as soon as you can. Thanks!!! Here it is:

5454                                   1234
+    3636                                   5678
6363                                    4321
2323                                    8765
7676                                    1234
_______                           _________

A number puzzle 2009-05-17
From Gita:
Ok, we really need help for a homework problem due on Monday morning
I've been trying for 2 hours and can't figure it out---if I can't I'm not sure
how my son can....We've been given a puzzle with the following rules:
--The sum of each side must equal 15
--We can only use the numbers 1,2,3,4,5,6,7, 8
--A number can be used only once
(Hint: Think of all combinations of 3 numbers = 15)
--The puzzle looks like this:

_____ _______ ______

_____               ______

_____ _______ ______

15 pigs in 4 pens 2009-04-22
From Melissa:
A farmer has 15 pigs. He wants to put them all into 4 pens, have an odd number of pigs in each pen, and have no pigs left over. Also, he isn't thinking about having any for dinner, as they are his pets.
How does he do it?

What is the original number? 2009-04-16
From Yueh:
A five digit number is written on a blackboard. Ron erases one of the digits and adds a newly constructed number to the original one. The result is 41751. What is the original number?
A number puzzle 2009-04-15
From Julie:
Hi, please help me!!! I have a subtraction puzzle... 5 digits minus 4 digits = 33333 Only using numbers 1-9 once each. I can get 33323 but then thats it!!! Please how do I work it out? There must be a simple way?? Thankyou
Four identical lots 2009-03-30
From Marina:
I really want to know the answer to this problem for my 6th grade son. I've already sent this question with the drawing but I couldn't send it correctly. I hope this one will pass through. Q: Divide evenly and identical the figure representing a lot, into four for the 4 siblings. I've sent a figure drawing as attachment. I will describe this in case it will not reach you: its a square divide into 4 triangle and 1 triangle is taken out living a letter M figure and this letter M figure is the one that will be divided.into 4 even and identical parts.

Marina

Stacking eggs 2009-03-12
From Prashanth:
if you stack two eggs eah in row you must get 1 balance
if you stack three eggs eah in row you must get 2 balance
if you stack four eggs eah in row you must get 3 balance
if you stack five eggs eah in row you must get 4 balance
it goes on like 6 , 7 , 8 and finally
if you stack nine eggs eah in row you must get 8 balance what would be the answer and how to reach it

Where do X, Y and Z go? 2009-02-27
From Aj:
A E F H I K L M N T V W
B C D G J O P Q R S U

where do X, Y and Z go?

A four digit number 2009-02-12
From alex:
the number of tens plus the number of hundreds equals the number of thousands. the number of ones is half the number of tens and one more than the number of hundreds the hundreds digit is 2. what is this four digit number
Dividing the digits 1 - 9 into two groups 2009-02-09
From donna:
using the numbers 1 to 9 can you arrange these into 2 groups, both of which have the same total, and no you cant turn the 6 upside down
The resulting number is the square of an integer 2009-01-30
From Randy:
A positive integer n is chosen. Then the product n ( n + 1 ) is computed and two digits are appended to the end of the product. The resulting number is the square of an integer.

Show that it is always possible to complete the process above or give a positive integer n for which the process cannot be completed.

Answered by Chris Fisher and Claude Tardif.
How many students were there 2009-01-25
From sooos:
After a math lecture in university, the students go to the cafeteria. EACH ONE of them buys a cheese sandwich and a cup of tea. They ALL pay \$18.49. How many students were they?
Who am I? 2009-01-09
From daphne:
im a 2-digit number less than 85.the sum of my digits is 9.the number in my ones place is twice my tens digit. who am i?
Answered by Robert Dawson and Harley Weston.
50 coins with a value of \$1.00 2009-01-08
From Ana:
you have 50 coins which have a total value of 1.00. What are the coins and how many of each do you have?
A 4-digit number 2009-01-05
From Anya:
It is a 4-digit number

The tens are double the ones.

The thousands are double the tens.

The sum of the digits is 19.

What number is it?

Two numbers 2008-12-15
From HERB:
I am thinking of two whole numbers. When I add them , their sum is 123. When I subtract the lesser number from the greater number their difference is 45. What are my numbers?
I am a whole number less than 100 2008-12-03
From Cecelia:
If I am a whole number less than 100
and the sum of my digits is 4
and half of me is an odd number
What number am I?
Also am I prime or composite?

A 4 digit number 2008-11-06
From Chris:
numbers 0 - 9 form a 4 digit number with no repetition.

It would round to 3000 if rounded to the nearest thousand

The digit in the tens place is twice the value of the digit in the thousands place.

It is an odd number.

It contains the largest digit.

It contains one digit less than 2.

The digit in the hundreds place is odd.

Can you find the 2 numbers?

Divide \$100.00 between two friends 2008-08-31
From anna:
divide \$100.00 between two friends, so that one has \$5.50 more than the other
Four weights 2008-08-25
From Darla:
A balance had known weights of 1/2 lb, 1/4 lb, 1/8 lb, and 1 oz. Edna's object weighted 2 oz. more than Paul's. Each used 3 known weights to weight his or her object. which know weights did each use?
???? x ? = ???? 2008-07-20
From waiyan:
????
x ?
????
using 1 2 3 4 5 6 7 8 9

Girls, cats and kittens 2008-05-16
From leria:
There are 7 girls in a bus. Each girl has 7 backpacks In each backpack, there are 7 big cats For every big cat, there are 7 little cats.

How many legs are there in the bus? One hint? it's a 6 digit number

seven + eight = twelve 2008-05-07
From evelyn:
My son's teacher has given the children this question to answer and I do not have an anser.

seven + eight = twelve

1?2?3?4 = 7 2008-04-25
From john:
1 2 3 4 = 7

The numbers have to stay in order of 1234 and when added,subtracted,multiplied or divided they have to equal 7.

A square garden of tulips 2008-04-08
From Vincent:
Each year Brandon plants tulip bulbs in a square flower bed. This year Brandon's flower bed has 29 more bulbs than it had last year. If the flower bed is still square how many tulip bulbs are in it this year?
A number puzzle 2008-03-22
From Cassidy:
1. Number has three digits
2. The second digit is an odd number
3. The first and third digits are even numbers
4. The number can be divided by five, six, and seven with a remainder of four.

How do you even start this type of problem?

5 9 1 6 10 12 2, where does 3 fit in and why? 2008-03-22
From Cassidy:
number sequence

5 9 1 6 10 12 2, where does 3 fit in and why?

Moving grain across the river 2008-03-12
From Janice:
Wesley needs to move 820 kg of grain across the river in a canoe that can carry no more than 120 kg. Wesley has a mass of 70 kg. What is the fewest number of trips he will have to make? A. 17 trips; B. 18 trips; C. 32 trips; D. 33 trips.
Separate three different sized marbles 2008-03-07
From Jana:
hello, I love this site, it explains everything so well. I have been asked a question in science, it asks for me to make a devise which separated three different sized marbles. I have thought this through alot but it still never makes sense to me. Everything i seem to think of never works out or has something that will make it not work. I'm really stuck on this one...please help me..! Thankyou so much Jana
From Sylvia:
There were 4 people sitting in a row, truing to win \$50.00 from a riddle.

The one in front was wearing a red hat. The second from the front was wearing a blue hat. The third from the front was wearing a red hat. The last was wearing a blue hat and is blind-folded.

Each of them were informed that they are all wearing a hat, the last person is blind-folded and that there are 2 red and 2 blue hats. If they can guess the colour of their hat, then they win the prize.

There was a long silence, then one of them guessed the color of his hat correctly. Who was it? and explain why.

(note that they can only see the person in front of them and are not allowed to turn around and see behind them.)

I am a 4-digit number 2008-02-12
From Nickie:
I am a 4-digit number with no repeating digits. I am divisible by 5, my first two digits (left to right) make a number divisible by 3, and my first three digits make a number divisible by 4. Also, my digits have a sum of 19 and I have the digit 7 in the thousands place. Who am I?
Women, cats and kittens 2008-02-12
From Paige:
There are 7 women on a bus. Each has a backpack. In each backpack there are seven cats. Each cat has seven kittens. How many legs are there total on the bus?
Bales of hay 2008-02-06
From mark:
5 bales of hay are weighed 2 at a time in all possible ways. The weights are
110
112
113
114
115
116
117
118
120
121
How much does each bale weigh

Answered by Stephen La Rocque and Penny Nom.
A relationship between numbers 2008-01-24
From Robyn:
Study these problems: ? 2=4 ? 5=25 ? 9=81

1. Explain what ? means (hint there are two answers).
2. What number is equal to ? 6
3. What number does ? 12 represent?

Answered by Stephen La Rocque and Penny Nom.
A 3 digit number 2008-01-23
Consider a 3-digit number,abc,where a is not equal to c.Switch it so that it becomes cba.Subtract the lesser from the greater to obtain rst.Switch this so that it is tsr.Prove that rst+tsr=1089
Partitioning a clock face 2007-12-19
From Kim:
Using a clock with a regular circular faced dial, draw two straight lines such that the sum of the numbers in each of the three areas is equal.
Answered by The team at Math Central.
A 3 digit number 2007-12-13
From Kim:
Find the number from the following clues:

A) is is a 3 digit even whole # divisible by 5
B} Each digit is different
C) Its hundreds digit is greater than its tens digit
D) It is less that 400, divisible by 3, and has only 1 odd digit.

A math trick 2007-12-10
From Megan:
I need to write a mathematical explanation of why this works!

Start with a four digit number. (a positive integer, and all digits can NOT be the same. At least one must be different)
Rearrange that four digit number.
Subtract the smaller 4-digit number from the larger.
Now circel one digit. (canNOT be zero, because that is already a circle)
Now re-write that number excluding the circled digit.
Compute the sum of the digits.
Now write down the next multiple of 9 that is larger than the sum.
Subtract the Sum from the multiple. (multiple - sum of digits)
Report Difference = to number circled.

The resulting number should be the number that originally circled.

Two logic problems 2007-12-07
From Grace:
1. You are an archaeologist that has just unearthed a long-sought triplet of ancient treasure chests. One chest is plated with silver, one with gold, and one with bronze. According to legend, one of the three chests is filled with great treasure, whereas the other two chests house a man-eating python that can rip your head off. Faced with a dilemma, you then notice that there are inscriptions on the chests:

Silver Chest - Treasure is in this Chest.
Gold Chest - Treasure is not in this Chest.
Bronze Chest - Treasure is not in the Gold Chest

. You know that at least one of the inscriptions is true, and at least one of the inscriptions is false. Which chest do you open?
(a) Silver (b) Gold (c) Bronze

math puzzle 2007-11-29
From Will:
This is a math puzzle called "What's my number"
1. It is a three-digit whole number.
2. It is a square number.
3. It is divisible by 5.
4. it is not an even number.
5.Each of it digit is not different.
6. It is divisible by 9.
7.It is less than 500.
8. Its ones digit is 5.
9.It has only one odd digit.
10. Its tens digit is less than its ones digit.

Rotating letters 2007-11-26
From sherry:
Ms. Thomas said to her class, when my older was little his nickname was Zed. The nickname my brother gave me was like his but with the first letter turned 90 degrees the second letter changed to the first letter of the alphabet and the third letter turned a half rotation. Does anyone know what my nickname was. My brother gave me the nickname because I slept too much. Could you please explain this to me so I can help my child solve it. Thanks
A 5-digit whole number 2007-11-19
From sunjoo:
a friend tells you to think of a 5-digit whole number. then do the following in order : multiply the number by 2. add 200 to the result. divide the result by 2. subtract 100 from the result. what is the greatest number you can get as an answer?
Elimination of mayan prisoners 2007-11-19
From Jim:
An evil Mayan emperor decides to make an example of 1,000 prisoners. He stands them in a circle with numbers one to a thousand marked on their shirts. He then starts counting: "one in, two, in three out" The third man is immediately executed. This continues round and round and round the circle. While the number in the circle shrinks, every third prisoner is pushed out and executed. And it continues even when there are only two prisoners left alive. What number is on the last prisoner's shirt?
EFGH x 4 = HGFE 2007-11-13
From ROBIN:
FIND THE NUMBERS THAT EACH LETTER STANDS FOR IN THE PROBLEM BELOW.

EFGH x 4 = HGFE

A number puzzle 2007-10-31
From matthew:
please help.make 200.take 4 numbers from the numbers 1-9,place the numbers into a square containing 4 equal squares 1 number to each square.example 13
57
you now have 4 sets of numbers 13 ,57 ,reading across and 15 , 37. reading down i have to find 2 or more ways of making i have to find the numbers that when added together using this method make 200.you can only use each number once.

Paying with silver - Part 2 2007-10-17
From Shanna:
The paying with silver problem. I understand how to do the problem, but could you please explain how you would use base 2 arithmetic to solve it.
4 odd numbers that equal 21 2007-10-15
From gary:
4 odd numbers that equal 21
Show that there is no five-digit number which 2007-10-04
From Greg:
show that there is no five-digit number which uses each of the digits 1,2,3,4,5 such that the numbers formed by the first digit is divisible by 1, by the first two digits is divisible by 2 by the first three digits is divisible by 3, by the first four digits is divisible by 4, by the first five digits is divisible by 5
How can that be? 2007-09-26
From Ken:
Al and I have 10 computers on a shelf 10 Team Members came passing by Each took a computer off the shelf, leaving 9 computers still on the shelf How can that be?
Find my number using the following clues: 2007-09-18
From T:
Find my number using the following clues: my number will make an array 2 rows wide my number is greater than 5 my number is less than 30 my number will make a square array my number is________? I was not sure where to begin with this word problem - can you help?? Thank you, T
Cutting a cake 2007-09-13
From Bibi:
how can one cut 8 pieces from a round cake with 3 straight slices of a knife, without moving any of the pieces? Help me explain this..
Dividing a pizza 2007-09-07
From maryjane:
how do you divide a pizza into eight parts using only three cuts?
Answered by Chris Fisher and Stephen La Rocque.
4,18,48,100, __ 2007-08-07
From Jeremy:
What is the next number in the following sequence?
4,18,48,100, __

Answered by Leeanne Boehm and Stephen La Rocque.
From JYOTI:
the letters in the alphanumatic addition are all different. find the numbers indicated in codes. all letters are digits from 0 to 9. SEND+MORE=MONEY.
Total of 100 with 1, 2, 3, 4, 5, 6, 7, 8, 9 2007-05-20
From Tyler:
use all the numbers shown, any of the following four operations +,-,x, and division and parentheses to make a total of 100. You may not change the order of the numbers, or use them more than once. 1 2 3 4 5 6 7 8 9 Please help asap I can't figure this out. Thank you Tyler
How old will they both be when ... 2007-04-03
From JOHN:
Lisa is 15 years old. Marcus is 49 years old. How old will they both be when Marcus is three times as old as Lisa?
An inheritance problem 2007-03-23
From Carl:
A father of 3 boys, who owns 17 horses dies. He leaves his first son 1/2 of the horses. The sons hate each other. The father leaves the second son 1/3 of the horses. They are ready to kill each other. He leaves his youngest son 1/6 of the horses. Without cutting the horses into pieces how do they split the horses? I heard this puzzle when I was 12 years old. 1968 The preacher rides up on his horse and said "If I give you my horse will you quit fighting ? They agree to stop fighting?" Why?
The game of 24 2007-03-22
From Britney:
I have a math problem with the game 24. I am not sure how to solve it. You can use +, -, multiplication, division, ( ), square root, and exponents. Please help me. The numbers are 1, 6, 7 and 8. You have to use all the numbers and you can only use them once.
What is the remainder when 3^2007 is divided by seven? 2007-02-18
From Chris:
What is the remainder when 3^2007 is divided by seven??
How many socks must you take from the drawer? 2007-02-18
From Gary:
Suppose you have 6 striped socks and 4 red socks in a drawer. How many socks must you take from the drawer to be certain of having a pair of red socks?
Weightng coins 2007-02-18
From Gary:
You are considering buying 27 silver coins that look alike, but you have been told that one of the coins is a lightweight counterfeit. Find the least number of weighings on a balance scale that you can use to be certain you have found the counterfeit coin.
*** x ** = **** 2007-02-16
From Dani:
Use the numbers 1-9 only once to make the following: A three digit number times a two digit number that gives a four digit number. That is *** x ** = **** (the numbers 1-9 can only be used once for each star). I came up with the answer 138 x 42 = 5796 but I want to know whether this is the only solution and if not, is there a formula to come up with the answer. Thanks! I appreciate your help!
Answered by Chris Fisher and Claude Tardif.
Centimeters to cubic meters and grams to kilograms 2007-02-14
From Colleen:
A box of balls measures 120cm by 20cm by 20cm and weighs 48 g.
One thousand boxes = x cubic meters and weighs x kilograms.
Also, one million boxes = x cubic metes and weighs x kilograms.
One billion boxes = x cubic meters and weighs x kilograms. Solve for x.

More on a man and his wife on an escalator 2007-02-02
From Patrick:
Hello, I was helping my son with a homework problem and came across a very similar on your site:

http://mathcentral.uregina.ca/QQ/database/QQ.09.01/monty1.html

We are trying to understand the answer shown. There seems to be leap, in the answer that isn't explained or we can't see it. Specifically in the answer it says:

"We know that the woman olny walks 21 steps to reach the top, and thus in the time she walks 7 more steps the escalator also goes up 7 steps. Hence the woman and the escalator are travelling at the same rate."

We understand that she still has 7 steps left, but how is it that you can conclude from that (or other factors) that during those 7 steps the escalator will also travel 7 steps.

Can you make a square out of a right triangle by using only one straight line? 2007-01-26
From Debra:
Can you make a square out of a right triangle by using only one straight line?
Answered by Stephen La Rocque and Penny Nom.
Fill in the signs 2006-12-07
From Ujwala:
4\$4\$4\$4=20 Fill in the signs in the place of dollor symbol.
27 snakes in four cages 2006-12-05
From Sherril:
A zookeeper has to put 27 snakes in four cages. His problem is that he must have an odd number of snakes in each cage. How can he accomplish this? You can put any number of snakes in a cage as long as the total number of snakes in each cage is an odd number.
Answered by Stephen La Rocque and Penny Nom.
Pick any prime number greater than 3,square it ,then ... 2006-11-20
From Eliseo:
I was ask to pick any prime number greater than 3,square it ,then subtract 4, then divide the new result by 12 and record the remainder. He told me the remainder was 9. How could he be sure that the remainder was 9 without knowing which prime I picked?
How can half of 12 be 7? 2006-11-16
From Liz:
How can half of 12 be 7?
Answered by Steve La Rocque, Chris Fisher and Penny Nom.
Where did the extra unit come from? 2006-11-03
From Daniel:
There are two triangles each with a base of 8, a height of 3 and an area of 12 units squared and two trapezoids, each with a one parallel side that is 3 and one that is 5 and a height of making it have an area of 20 units squared. When arranged in a 8x8 square then the total area is 64 units squared, but when arranged in a 5x13 rectangle the total area is 65 units squared, where did the extra unit come from?
Replace the blanks with + or - to make the statement correct 2006-10-13
From Molly:
Hi my name is molly, and I have a question I can't answer and need your help. I am a student. This is the qustion:
Try to replace the blanks below with + or - to make the statement correct
1_2_3_4_5_6_7_8_9 = 1

A 5x2 rectangle 2006-10-03
From Stanley:
Cut a 5x2 rectangle into 4 pieces, and then put them back into as a square.
Answered by Claude Tardif and Penny Nom.
10 friends run into each other at a bar 2006-08-19
From Ken:
10 friends run into each other at a bar. We will name them A,B,C,D,E,F,G,H,I AND J. They all leave at the same time heading for seperate bars. However, A runs into B, C runs into D, E runs into F, G runs into H and I runs into J. These five groups leave again and the same thing keeps happening, but each time running in to someone they have not run into before. How many bars will it take, with each person meeting the others only once, until all of them have met each other again?
Two water jugs 2006-07-05
From Kisha:
suppose that you have two water jugs, one which holds three gallons and one which holds five gallons. in additions, you have a water faucet at your disposal. your job is to find a method that produces exactly one gallon of water, another method that produces exactly two gallons of water, another method that produces exactly three etc up to exactly eight gallons of water. you may fill jugs from the faucet or from one another. you may not rough estimates???
A number puzzle 2006-06-30
From Atitya:
The diagram given below consist of seven line segments and six circles,place the numbers 1 to 13 on either a line or a circle in such a way that the numbers on each segment is the difference of the two at its end points.
Answered by Stephen La Rocque and Penny Nom.
As close to 841 as possible 2006-06-21
From Alan:
using these numbers by either add subtract division multiply come up with the answer as close to 841
100 25 10 7 6 3

How much did I have in my wallet when I lost it? 2006-06-15
From Marangeo:
I recently lost my wallet and when it came to completing the police report I couldn't remember how much money I had in there. I do remember thinking that the first time I bought something that it cost me 10 per cent of what I had. Then I noticed that the second purchase had also cost me exactly 10 per cents of what I had left. My receipts totalled \$19. How much did I have in my wallet when I lost it?
What is the probability that the policeman will shadow the correct person? 2006-06-14
From Kolby:
Through an informer from the underworld, the police know the meeting place of a gang. The identity of the different gang members, however, is unknown. it is the duty of a policeman to shadow the leader of the gang. The policeman knows that the leader is the tallest of the five persons, all of whom have different heights. after the meeting, the gangsters, as a safety measure, leave the building separately at intervals of 5 minutes. As the policeman cannot see who is the tallest, he decides to let the first two gangsters go and shadow the one after that who is taller than all those who left before.Through an informer from the underworld, the police know the meeting place of a gang. The identity of the different gang members, however, is unknown. it is the duty of a policeman to shadow the leader of the gang. The policeman knows that the leader is the tallest of the five persons, all of whom have different heights. after the meeting, the gangsters, as a safety measure, leave the building separately at intervals of 5 minutes. As the policeman cannot see who is the tallest, he decides to let the first two gangsters go and shadow the one after that who is taller than all those who left before. What is the probability that the policeman will shadow the correct person?
Answered by Steve La Rocque and Claude Tardif.
How many people are in the race? 2006-04-07
From Marty:
You're in a race with 1/5 of the racers ahead of you and 5/6 of them behind you. How many people are in the race?
A number puzzle 2006-03-22
From A teacher:
Students brought this website to my attention and asked why this puzzle worked... I'm not sure. The url is: http://digicc.com/fido/ and it tells you to choose a 3 or 4 digit random number with different digits. Write it down, rearrange, subtract the smaller from the larger. then circle a nonzero digit, type the remaining digits into the space provided and they will tell you the number you circled. Can you provide the reason that this works.
Answered by Claude Tardif and Penny Nom.
8,_,4,9,1,_,10,3,_,0 2006-03-08
From Rachel:
I cant figure out this sequence if someone could help me 8,_,4,9,1,_,10,3,_,0
2,4,9,6,5,6,____,____,____,... 2006-03-06
From Mike:
I am having problems figuring out the following sequence:

2,4,9,6,5,6,____,____,____,...

We were able to guess that the pattern simply started to reverse itself, but I was wondering if there were other possibilities.

The nth term 2006-03-05
From Umar:
my question is what is the nth term for a house of cards 4 stories high if you use the following numbers:
2 7 15 26

Separate 35 into two parts such that 4 times the larger is 4 less than five times the smaller 2006-03-01
From Barbara:
Separate 35 into two parts such that 4 times the larger is 4 less than five times the smaller
Luke and Slim have only one horse. 2006-02-26
From Emily:
Luke and Slim have only one horse. Luke rides for the agreed on distance and then ties up the horse for Slim, who has been walking. Meanwhile, Luke walks on ahead. They alternate walking and riding. If they walk 4 miles per hour, and ride 12 miles per hour, what part of the time is the horse resting?
The nth term of a sequence 2006-02-21
From Mike:
I'm having trouble finding the nth term in an equation, can you help me?
Whose photo is he looking at? 2006-02-19
Looking at a picture a man says, that the father of the person (in photo) is the son of my father. whose photo is he looking at?
Zhi Wei was born on christmas day in 1983. 2006-02-14
From Clement:
Zhi Wei was born on christmas day in 1983. His father shares the same birthday, but he was born in 1951. In which year will Zhi Wei's age be exactly 1/3 of his father's age?
From Jayne:
The question is to use the numbers 1 through 9. They are to be placed on lines, and each group is to add up to 11. The trick is that the first 2 numbers used add to 11, then lines 2, 3 and 4; then lines 4,5 & 6; then lines 6,7 & 8; and then lines 8 and nine (it is really hard to describe. In the book, is shows circles making each group). The lines are all horizontal, and lined up to each other like:_ _ _ _ _ _ _ _ _
More on the game of 24 2006-02-02
From Cathy:
10,16,9,4 this numbers have to equal up to 24. we can't figure it out.
Make 2 rows of 4 circles with only 6 circles 2006-01-31
From Sarah:
Moving as many circles as you need, make 2 rows of 4 circles only having 6 circles?
Who is lying? 2006-01-14
From Diane:
A business man was working in his home office when he realized he had left a five-dollar bill in the book he had been reading. He called his butler to bring him the book from the library. When he got the book, the bill was no longer there. He then questioned the maid and the butler. The maid remembered seeing the bill between pages 99 and 100 in a book to the left of a business book. The butler did not recall seeing the bill, but was sure the book was to the right of the business book, because to the left of it there was a statistics book. Who is lying?
Twelve golf balls 2005-12-28
From Todd:
You have 12 golf balls and 11 of them are the exact same weight, but one of them is either a little heavier or a little lighter. You only have three attempts to weigh the balls. How can you determine which ball weighs more/less than the rest?
Two dogs and a flea 2005-12-23
From Michelle:
Two dogs, each traveling at 10 ft/sec, run toward each other from 500 feet apart. As they run, a flea flies from the nose of one dog to the nose of the other at 25 ft/sec. The flea flies between the dogs in this manner until it is crush when the dogs collide. How far did the flea fly?
Complete the array 2005-12-11
From Ginger:
 4 0 2

Make the sum of these number add up to six.

Going across, down, corner to corner. Using the number 4, 2, 0 only.

Fill in the blanks 2005-12-05
From Bonnie:
Distribute the numbers 1 through 9 on the lines below so that two equations are true.

_ _ x _ = _ _

_ x _ = _ _

Use each digit only once-

Add one 1 at the beginning and at the end of a number 2005-11-13
From Samuel:
If we add one 1 at the beginning and at the end of a number, this number is increased by 14789. What is the sum of the digits of the number?
What number am I? 2005-10-27
From Samantha:
First 8 is added to me, then I am multiplied by 6. Then 40 is subtracted from me. Finally, I am divided by 10. The result is 11. What number am I?
What is the number? 2005-10-10
From Jess:
One eighth of the square root of 7 less than a number is 2. What is the number?
Two groups that have equal sums 2005-09-30
From Anita:
using the numbers 1, 2, 3, 4, 5, 6, 7,and 8. how do we divide them into two groups so that they have equal sums?
A multiple-choice and true-false exam 2005-09-28
From Kiat:

Harry, Neville, Ron, Hermione and Malfoy each answered five questions on O.W.L. exam consisting of two multiple-choice questions (A, B or C) and three True-False questions. They answered the questions as follows:

Student Q1 Q2 Q3 Q4 Q5
Harry A A T T T
Neville B B T F T
Ron A B T T F
Hermione B C T T F
Malfoy C A F T T

If no two students got the same number of correct answers, who got the most correct answers? And what is the correct answer for each question?

Use the numbers and symbols only once to come up with the answer 2005-09-19
From Kaitlyn:

Question: I have math problem that no one in my class was able to solve but the teacher said it does have an answer. We need to use the numbers and symbols only once to come up with the answer:

36 18 12 6 + - ( )

______________________________ = 41

The trinity concept says three is one. 2005-09-17
From Kevin:

The trinity concept says three is one. Mathematically, I will attempt to proof this.

G = T
2G = 2T Double both sides
G + 2G = G + 2T Add G on both sides
3G = G + 2T Simplify
3G - 3T = G + 2T - 3T Subtract 3T on both sides
3(G - T) = G - T Factor 3 on the left, simplify on the right
3 = 1 Divide (G - T) on both sides.

But how can three equals one? Can it?

What is my number? 2005-09-16
From Bob:
I have 6 digits. 100,000th digit is one less than my ones digit, eight greater than my 1,000's digit, twice my tens digit and four times my 100s digit. My 10,000s digit is 0 What is my number?
Who is taller: John or Mary? 2005-09-14
From Ulises:
All the students in a school are arranged in a rectangular array. After that, the tallest student in each row was chosen, and then among these John Smith happened to be the shortest.Then, in each column, the shortest student was chosen, and Mary Brown was the tallest of these. Who is taller: John or Mary?
Answered by Penny Nom and Claude Tardif.
Cows, chickens and pigs 2005-09-10
From Markequetta:
I was asked a question by a friend who refuses to give the right answer to a question that I answered wrong. So if you can help me that would be great! The level of my question is secondary I believe.

Question:

Cows cost: \$10
Chickens cost: \$0.50
Pigs cost: \$3

You have to buy 100 animals and spend \$100, so how many cows, chickens, and pigs do you have on your farm?

1_2_3_4_5_6_7_8_9 = 1: Fill in the blanks 2005-08-26
From James:
Try to replace the blanks below with + or - to make the statement correct
1_2_3_4_5_6_7_8_9 = 1

A set of numbers whose sum is 1 2005-07-21
From Santos:
Does there exist a set of numbers whose sum is 1, and the sum of whose squares is less than 0,01?
5+5+5=550 2005-05-30
From Bill:

5+5+5=550

This is a math equation that is not true. How can it be made to be true by using only one line?

A flaw in a problem 2005-04-15
From Bryce:

Question:

(x2-x2) = (x2-x2)
x(x-x) = (x+x)(x-x) [divide both sides by (x-x)]
x = x + x
x = 2x [divide both sides by x]
2 = x/x = 1

Where is the flaw in this problem?

Half of five 2004-12-26
From Pauline:
Why is four half of Five? Hint: It's the middle half?
Slicing cubes 2004-11-23
From Anthony:
You are working with a power saw and wish to cut a wooden cube 3-inches on aside into 27 1-inch cubes. You can do this by making six cuts through the cube keeping the pieces together in the cube shape. Can you reduce the number of necessary cuts by rearranging the pieces after each cut?
Planting trees 2004-11-15
From Heather:
Design a plan of how it would be possible to plant 10 trees in 5 rows, and have 4 trees in each row.
Driving me crazy 2004-09-18
From Jerry:
This is driving me crazy!!! Someone told me of a number that can be divided EQUALLY by each of the following individual numbers: 1,2,3,4,5,6,7,8,9. what is that number?
A challenge 2004-09-17
From Lasse:
xy
xx
xyx
xxx
xyxx

"x" and "y" each represents a number. Find out the system to make the next line

How to dry matches 2004-09-06
From Liz:
The neighbors of a young man who needed seclusion for a few days offered him the keys to their cabin in Maine. Arriving there on a damp and cold autumn evening he saw that while the cabin had normal running water and electric lights, for heat it had only a pot-bellied stove. Fortunately, there was plenty of wood, kindling, newspaper, and matches. Being an experienced hand at making a fire, he opened the damper, put into the stove crumpled newspaper, and properly stacked the kindling and logs. The matches, however, wouldn't light. They were too damp from the humidty. The nearest town was 30 miles away, and, anyway, it was late. What next?
Nine minutes 2004-09-02
From A student:
You have two hour glasses-one measures 7 minutes and one measures 4 minutes.How can you time 9 minutes?
Two water jugs 2004-08-16
From A student:
You go to a source of water with two jugs and only two jugs. One jug has a capacity of exactly three pints and the other five pints. Both jugs are opaque (you can`t see inside them) and irregularly shaped. You have no other water containers. You do not have a scale. How can you use the two jugs and only the two jugs to measure exactly four pints of water?
Two puzzles 2004-07-13
From Fred:
A young man's car developed a flat tire while he was driving along a deserted street. He pulled over to the curb and did all the usual things; removed the hub cap; unscrewed the lugs and rested them carefully in the hub cap, jacked up the car. As he was putting the spare tire onto the axle he accidentally kicked the hub cap. The lugs rolled out, and all five of them rolled down a nearby grate. Peering through the bars of the grate the man thought he could see the lugs about 6 feet below in a shallow water puddle. He had a problem, how do you think he solved it?

It is noon, your lunch hour, but you can not go out because there is a terrific hailstorm. Turning on your radio you hear the weathercaster predict that the hail will change to rain and that it will pour all day today. How can you determine the sun will be shining in 36 hours? Justify your answer.

Pick a number greater than 1 2004-06-25
From A student:
I understand that when you pick a number greater than 1 and less than 10; multiply it by 7 and add 23, then add the digits of that number until you get a one digit number. Then multiply that number by 9, add the digits of that number until you get a one digit number, subtract 3 from that number and divide the difference by 3; that this process will always give you the result of 2. Does this have a name or theory for it as to why the answer will always be 2?
Integers 2004-06-10
From A parent:
I have an odd 3 digit product. My factors are a 1-digit number and either or 2- or 3-digit number. My factors are odd, but neither is 1. Find my factors and my product.
There is one answer. What is it?

A clock chimes 7 times in 7seconds 2004-05-02
From Anna:
A clock chimes 7 times in 7seconds. how long does it take the clock to chime 10 times?
Marching legion 2004-04-24
From Art:
A column of soldiers is 100 meters long. Their sargeant at the rear of the column gives the order to march. The sargeant marches alongside the column to its head and then back to the rear, at which point he gives the order to halt. In all, the column of soldiers has marched 100 meters. How far has the sargeant marched? I say 187.5 meters, but those who teach or who have taught mathematics tell me no. Some say much more and some different. What do you say?
The "22" puzzle and the "1089" puzzle 2004-04-22
From Marcelle:

1. Choose 3 digits from 1-9
2. Make all the 2 digit numbers you can from these (6)
3. Add the 3 original digits and divide them into the sum from step 2.

Another one related to this is it:
1. Choose a three digit number ensuring the first and third digit are differnt by at least two.
2. Make the reverse three digit number and subtract the smaller one from the larger of these.
3. Take this answer and reverse it and add these two 3 digit numbers .

eg:
643 - 346 = 297
297 + 792 = 1089

it doesn't matter what numbers are used, the results are alwasy the same. eg 22 or 1089

Numbers around a circle 2004-03-28
From Rebecca:
my maths question is use the numbers 1,2,3,4,5,6 and 7 place each number in a circle so each line adds up to 12. There are seven circles, six on the outside and one in the middle. Each number lines up with the middle number and the outside numbers line up with the one directly across from it as if a line was going through the middle number circle.
Three jugs 2004-02-26
From Shelly:
You have three jugs: A 6 Liter, 4 Liter and a 3 Liter. Your goal is to get exactly 5 Liters of liquid in the 6 Liter jug. Your supply of liquid is unlimited and there are NO markings on the containers. You cannot do halves.
Will be shinning in 36 hours? 2004-02-08
From Kim:
It is noon, you lunch hour, but you cannot go out because there is a terrific hailstorm. Turning on you radio you hear that weathercaster predicts that the hail will change to rain and that it will pour all day today. How can you determine whether the sun will be shinning in 36 hours? Justify your answer.
A riddle 2003-11-19
From Sarah:
Ok, our teacher gave us this riddle, and I cannot for the life of me figure it out. He said that there are three problems with the following proof:
Three problems 2003-11-16
From Megan:
My name is Megan and I am a junior in high school. Our teacher gave us a few xtra credit questions and I need some help.
10,000 2003-10-08
From Nathan:
what two numbers make the product of 10,000. Neither number can end in a zero
I can Guess your birthday 2003-08-29
From Michelle:
Hi I am trying to explain to my children how this problem works. It was sent to me on the internet and I can not figure it out. They keep asking me how it works and I can not tell them.

The problem is: "I can Guess your birthday::

A worm on a hill 2003-08-21
From Lisa and Samantha:
A WORM IS AT THE BOTTOM OF A 10 FOOT HILL. HE CRAWLS UP THE HILL 4 1/2 FEET A DAY. AT NIGHT WHEN HE REST HE SLIDES DOWN 2 1/2. HOW LONG DOES IT TAKE THE WORM TO CRAWL UP THE HILL.
A problem with lugs 2003-07-11
From Lori:
A young man's car developed a flat tire as he was driving along a deserted street. He pulled over to the curb and did all the usual things: removed the hub cap, unscrewed the lugs and rested them carefully in the hub cap, jacked up the car. As he was putting the spare tire onto the axle he accidentally kicked the hub cap. The lugs rolled out, and all five of them fell down a nearby grate. Peering through the bars of the grate the man thought that he could see the lugs about 6 feet below in a shallow water puddle. He had a problem. How do you think he solved it?
The sum of two numbers is 5 and their difference is 2003-06-16
From Akhil:
The sum of two numbers is 5 and their difference is 11. What is the product of the two numbers?
The square of my age was the same as the year 2003-04-14
From Pat:
Augustus de Morgan wrote in 1864, "At some point in my life, the square of my age was the same as the year." When was he born?
Jo's books 2003-04-07
From Miguel:
Jo announces, "I have more than 999 books."
Jean says: "No Jo! You have fewer than 1,000 books."
Mary says: "Jo has at least 1 book."
Only one of these statements is true. How many books does Jo own?

X times Y equals ten million 2003-02-26
From Baneen:
Would you be able to tell me which two numbers would compute ten million without any number having zeros in it?
Dorothy and the wizard 2003-01-24
From Ken:

dorothy was going to see the wizard of oz...she stopped at the bakery and bought a box of cookies.

she met the scarecrow and gave him half the cookies. she ate half of the remaining cookies and threw one half cookie away.

she met the tin man and gave him half the cookies. she ate half the remaining cookies and threw one half cookie away.

she met the lion. she gave him half of her cookies. she ate half the remaining cookies and threw the LAST half cookie away.

how many cookies did dorothy leave the bakery with?

The cousin of Sally's sister's boyfriend 2003-01-23
From Michael:
Sally went to a farm to buy eggs. Returning home, she gave half of them to her sister who, in turn, gave a third of those she had gotten to her boyfriend. The latter, after eating one third of the eggs that he had gotten, gave the rest to his cousin. Given that each egg weighs 70 grams, that Sally cannot carry more than 2.5kg, and that the eggs were raw, calculate how many eggs the cousin of Sally's sister's boyfriend received.
A penny, a nickel, a dime, a quarter, and a loonie 2003-01-21
From Blaine:
I have 5 coins: a penny, a nickel, a dime, a quarter, and a loonie. How many different amounts of money could I pay using any combination of these coins?
Jo's books 2003-01-21
From debra:
Jo announces: I have no more than 999 books.
Jean says: No Jo, You have fewer than 1,000 books.
Mary says: Jo has at least 1 book.

Only one of these statements is true, How many books does Jo own?

I do not know HOW to approach this problem and solve it.

NO RED-HATTED DWARVES ALLOWED 2003-01-14
From Dulce:

There are 1000 dwarves in Dwarfland. Now as you know, dwarves are born with either red or white hats on.

The dwarves in Dwarfland love to party. Every night, they all flock to the same club to dance the night away.

One day, a sign is posted at the club: "NO RED-HATTED DWARVES ALLOWED". A certain number of days pass, after which all of the white-hatted dwarves are in attendance,and none of the reds.

How did the red hats know not to come?

Assumptions:

1. The number of red and white-hatted dwarves need not be equal. There are at least 1 of each color.

2. There are no reflections or mirrors in Dwarfland (i.e. the dwarves can't see the color of their own hat), and no dwarf can reveal through direct or indirect means the color of another dwarf's hat.

3. There is NO COMMUNICATION among dwarves

4. No white-hatted dwarf ever misses a night of partying

A rope trick 2002-12-05
From Jerry:
My name is Jerry and I am a math teacher at the secondary school level in the greater Toronto area. I posed the following problem to my enriched grade 10 math class that I found in the book called "Mathematics and the Imagination" by William Kastner. According to the author, it is posible for two people linked to each other with two ropes around their hands, to separate themselves without letting go of the rope. The students had lots of fun trying to accomplish this problem using skipping ropes from the Phys Ed department, but with no success.
Making 7 2002-11-26
From Bill:
At one time I had the answer to this math equation but I have lost it and can't seem to regain it. I may be going at it wrong but as I recall there were the numbers 1 through 4, and the std operators, +, -, /, *, and parentheses. The object was to make the four numbers with the operators equal to 7. Each number and operator may be used only once. My 9 year old loves these quizzes but I can't give it to her if I can't provide the correct answer.
4 x abcd = dcba 2002-11-20
From A student:
Say you have a four digit number (e.g. abcd) and you multiply the number by 4. The answer you get will be the reverse order of the number you started with (dcba). What is the number? The four digits (a,b,c,d) cannot be the same number or cannot be repeated.
Answered by Penny Nom and Claude Tardif.
Three bags of marbles 2002-11-08
From A student:
I have 3 bags of marbles

1 bag is labeled blue; 2nd bag is labeled red; 3rd bag is labeled blue & red

all the bags are mismarked

your job is to take one marble from 1 bag look at it and correctly label all the bags

What are the digits? 2002-10-24
From Ebenezer:
There are three digits. The middle digit is zero and the sum of the first and last digits are is 13. When the number is reversed it is increased by 297. What are the digits?
Use each digit 1-9 only one time each,... 2002-10-19
From Megan:
Use each digit 1-9 only one time each, divide the numbers into 3 groups, make one 2 digit number, one 3 digit number, and one 4 digit number. There are 6 combinations of these numbers in which you can multiply the 2 digit and 3 digit number together to get the 4 digit number (using each digit 1-9 one time each). What are they!!!!!!!!!????????????
8 squares from 12 sticks 2002-10-08
From A student:
If you have 12 sticks the same size, how do you make them into 8 squares?
Number play 2002-09-24
From Julie:
Organize these numbers and the operations so that each equation is correct. Use each coice only once per equation.

36 18 12 6 - + ( ) /

_________________________ = 22

_________________________ = 41

A fish weighs 10 pounds more than half its weight. 2002-09-10
From Rebecca:
A fish weighs 10 pounds more than half its weight. How much does it weigh?
The community garden 2002-09-08
From Michele:
Bryce, Duanne, Juliana and Sonya share a 40ft by 48 ft rectangular portion of the community garden in the neighborhood. With this space each has their own rectangular garden plot.

-Bryce is the only one with a square plot. its are is 1/2 the area of Duanne's -The area of Bryce's plot is 2/3 the area of Julianna's plot. Their plots have one side in common.

-Sonya's garden has an area twice that of Julianna's garden.

What are the dimensions of each person's garden plot?

Place six numbers around a triangle 2002-07-19
From Monika:
I need to place six numbers around a triangle, as such that one number is on each corner, and one number on each side making three numbers in one line, adding up to two hundred exactly. The number I have to use are, 40, 50, 60, 70, 80, 90. I have to use each one once, there for, each number cannot be repeated.
Answered by Claude Tardif and Chris Fisher.
Can you make up a word that adds up to 1000000? 2002-07-19
My question is elementary and I am a student Please help me with the following conundrum, as it is driving me crazy.

'When the letters in the alphabet are given values from 1 to 26 for A to Z, can you make up a word that adds up to 1000000 ( one million )-used as a multiplication?'

Like 'cat' would be 3*1*20 = 60

100 from four 9's 2002-03-27
From A student:
My teacher gave us a math problem to try and figure out and I am stumped. The problem was this.... by only using four nines, how can you get an answer of 100? You can add, subtract, multiply or divide...anything you need to do ,but you can only use four nines.
A sequence 2002-03-07
From Caroline:
hi, here is the problem,

1
11
21
1211
111221
_ _ 2_ _ _

we can't get the sequence of the last line ,with the 3rd number being 2,thanks

What number am I? 2002-03-03
From Samantha:
I am an even number that has more ones than tens. My thousands digit is the quotient of 9 divided by 3 and my tens digit is the sum of 3 and 3. I have no hundreds. What number am I?......Please answer this for me...The answer I come up with is 3,060...Is this right?..
A hat of a different color 2002-02-24
From Kirstin:
A teacher made a deal with 3 of his students. He said that if you can guess what color hat you have on your head without looking, I will pass you. There were 2 red hats and 3 blue hats. The deal worked like this: The three students would close there eyes, and the teacher would put a hat on each of their heads and then hide the other 2. Then one at a time, the students would open their eyes and try to figure out what color hat was on their head. The student could guess or pass. This is what happened when they put their deal to the test: A boy named Arturo was first and opened his eyes but wasn't sure so he passed so he didn't get it wrong. Belicia was next and she passed too because she wasn't sure. Also she thought about the fact that Arturo didn't know. Carletta was last and without even opening her eyes, she knew for sure what color hat she was wearing and her answer was right. So i have to figure out what color hat she's wearing for sure.
I am a fraction 2002-02-01
From Anthony:
I am a fraction that is greater than 1 but less than 2. The sum of my numerator and denominator is 11. My denominator subtracted from my numerator is 1. What fraction am I?
Making 24 2002-01-17
From Renee:
My 4th grade daughter and I need to find a simple math sentence using 5, 5, 3, & 7 to equal 24. You can add, subtract, divide or multiple.
A sale on eggs 2002-01-17
From A student:
A store had a sale on eggs, selling 13 eggs for the usual price of a dozen eggs. As a result, the price of the eggs was reduced by 4 cents a dozen. What is the original price for a dozen eggs?
A 1 m by 1 m square box in the xy-plane 2001-12-15
From Murray:
Inside a 1 m by 1 m square box in the xy-plane, there are finitely many line segments, whose lengths sum to exactly 10 m. Show that there exists a straight line in the plane which crosses at least six of these line segments. (Hint: first, show that there exists a straight line in the plane which crosses at least five of these line segments.)
How do you get to 100 by using 6 nines? 2001-11-17
From A student:
How do you get to 100 by using 6 nines?
Subtracting 5 from 25 2001-10-05
From Melissa:
How many times can you subtract the number 5 from 25?
27 2001-09-10
From Kacy:
In class we were given this problem. We have the numbers 30, 29, 19,11,26. these numbers = 27 in some way but how? the numbers can be applied any way using + - / X ( ) but can only be used 1 time each. can you please help me.
Three fractions 2001-09-10
From Kathleen:
a/bc + d/ef + g/hi = 1

Each of three fractions has a one-digit numerator and a two digit denominator. The three fractions together add up to one. Place the nine digits 1-9 into the fractions to make the equation correct.

Two snakes 2001-08-31
From A student:
Two snakes(pythons,actually)of same size and shape start swallowing each other by the tail with the same speed. What will happen ultimately?
Water jars 2001-08-27
From Pe3te:
Stacie and Kacie each have a jar. Stacies jar holds 5 quarts of water and Kacies jar holds 3 quarts. The girls dad ask them to go get him some water from the pump and to get him 1 gallon of water (NO MORE NO LESS) The jars were not marked in any way. In ten minutes the girls where back with 1 gallon. How did they get exactly 1 gallon ?

1) there are two ways to do it I only no one. 1st answer is.....

How far does the fly fly? 2001-08-07
From Harold:
```
6 MPH                            4 MPH
Rachel  ----------------------     Eli
10 Miles apart
```

The fly is on Rachels handlebars. The fly is scared so it flys back and forth at 20 MP H. How far has the fly flown when Rachel and Eli meet?

f

5+5+5=550 2001-06-11
From Tom:
I am in algebra and my teacher gave us an equation that was not true. she told us that we could only use one line segment(it can't bend turn has to be straight) to make the equation true. here is the equation: 5+5+5=550. i have not figured it out but have tried many things and believe it is not mathmatical but cross a # or sign out.also i forgot you can't put a slash mark through the equals sign.
Where is the other \$1? 2001-06-05
From Samantha:
3 people go to a motel. The room is \$30. They split it \$10 each. While in the room the Mgr. tells the clerk the room was only \$25, so he gives her \$5 to take back to the 3 people. On the way she cant decide how to split the \$5 between the three people so she puts \$2 in her pocket and gives them \$1 each.....Therefore, the room now only cost the three people \$9 each, which is \$27 plus the \$2 the clerk pocketed,making a total of \$29.....Where is the other \$1?
Two jugs 2001-06-04
From Heather:
One goes to a source of water with two jugs and only two jugs. One jug had a capacity of exactly three pints and the other five pints. Both jugs are opaque (you canít see inside them) and irregularly shaped. How can you use the two jugs and only the two jugs to measure exactly four pints of water?
24 from 2, 2, 14, and 21 2001-05-08
From Kimberly:
using the numbers 2, 2, 14, and 21. how can you get 24 using + - X or division
The number of occurrences of 0 is __, of 1 is __, of... 2001-04-17
From Martyanne:
"In this sentence the number of occurrences of 0 is __, of 1 is __, of 2 is __, of 3 is __, of 4 is __, of 5 is __, of 6 is __, if 7 is __, of 8 is __, of 9 is __."

Each blank is to be filled with a numeral of one or more digits, written in decimal notation.

Two ferry boats 2001-03-25
From Gil:
Two ferry boats leave from opposite shores. One is faster than the other. They meet 720 yards from the nearest shore. They proceed to destination and upon returning they meet 400 yards from the other shore. What is the exact width of the river.
Math Puzzle 2001-03-10
From Vanessa:
I have a math puzzle. I have been working on it for over 2 weeks. Here it is: use the numbers 1-25 each only once. The rows across are an equation and the columns down are an equation. There are 25 boxes. You have to use the order of operation x and / first then = and -. Some of the answers are -numbers.
.
.
.

problem of the week 2001-03-06
From Peggy Allan:
My son has been challenged with "the problem of the week" and I am unable to assist him in finding a reasonable solution.

Problem 1,

Julio needs to draw a line segment 15cm long. He does not have a ruler. He does have some sheets of letter size paper 28 X 21.5 cm. Describe how Julio can use the paper to measur 15 cm.

23 + 17 * 2 / 8 + 11 = 13 2001-02-02
From David:
My child is working through basic operations, and gave this problem:

23 + 17 * 2 / 8 + 11 = 13

The teacher wants the parenthesis to be put in the right places to come up with 13.

Unscramble these words 2001-01-30
From Myosha:
Hi my name is Myosha. I would be part of the secondary(6~9) class. I need you to unscramble these words & define them for me.

1. edicnreeff

2. rtgeare

3. itfrnoca

4. lmicdae

5. sdvioini

6. imrretepe

8, 4, 2, 18, 1, 9 2001-01-11
From Neyra:
Place each number below in one of the blanks to create the most meaningful and realistic story possible.
Pizza delivery 2000-12-07
From Meghan:
3 men give 10 dollars each to a pizza deliver driver and when he gets back to his work the manager says to the pizza driver the bill was actually 25 dollar so he has to returns 5 dollars. on his way to the mens house he the driver decides to kept 2 dollars for himself and he gives 1 dollar back to each of the men. So each one of the men actually paid 9 dollars. but 9 times 3 is 27 plus the other 2 that the driver took equals 29 so where did the other dollar go.
Tapes and CD's 2000-10-22
From Arnold:
Nicole has 25 CDs and tapes altogether. When she tries to pair them up, she has 4 CDs left over. How many tapes does Nicole have?
Transporting bananas 2000-10-18
From Krystie:
A farm has 45 bananas, a man has to take a truck and transport 15 bananas to a market that is 15 miles away. Every mile he travels, he must eat a banana. I have to get at least one banana to the market
Cutting the cake 2000-10-05
From Cherie:
How can you divide a cake (circle) into 14 pieces by using only 4 straight lines?
Selling chickens 2000-09-12
From Rick:
A man raised chickens. He sold all but 8 of them. The first buyer bought 1/3 of all the chickens + 2/3 of a single chicken. The second buyer bought 1/3 of the remaining chickens + 1/3 of a single chicken. The third buyer bought 1/3 of the remainder + 2/3 of a chicken. How many chickens did the seller own before selling any? All chickens were alive and whole when the buyers received them.
A number problem 2000-09-02
From Lalita Balu:
Can you arrange 1234567890 to add up to 100?
Three pattern questions 2000-08-22
From Michael Rodriguez:
1. 6 and 7 = 42
2 and 5 = 10
4 and 8 = 8
5 and 9 = ?

2. 7 and 5 = 1
9 and 12 = 3
10 and 15 = 5
12 and 16 = ?

3. 1st = 1
3rd = DEF
10th = *
6th = ?

Searching for socks 2000-04-26
From Luther Jackson:
There are 10 red socks and 10 blue socks in a drawer. Aside from their color the are identical. All of the socks in the drawer are mixed up. If the room was pitch black, How many socks would you need to pull out of the drawer to be certain that you have a pair that matches? Why?
Paying with silver 2000-04-26
From Luther Jackson:
A silver prospector is unable to pay his March rent in advance. He owned a bar of pure silver, 31 inches long, so he made the following arrangement with his landlady. He would cut the bar, he said into smaller pieces. On the first day of March he would give her and inch of the bar, and on each succeeding day he would add another inch to her amount of silver. She would keep this silver as security. At the end of the month, when the prospector expected to be able to pay his rent in full, she would return the pieces to him.
.
.
.

Answered by Claude Tardif and Penny Nom.
Magic triangles 2000-04-11
From Sandy:
My tutoring student brought math homework today in the form of a "magic triangle". There are three spaces along each side for missing numbers. The sums of the numbers along each of the 3 sides should be the same. Use the numbers 4 through 9. Don't use any number more than once. The sum of the numbers on each side should be 20. What is the logic behind solving a problem of this kind?
Answered by Claude Tardif and Harley Weston.
White and blue paint 2000-04-09
From Lauren Emerson :
A truck full of cans of blue and white paint flips over on the road. There are dots of blue and white paint everywhere. Prove that two dots of the same color paint are exactly pi feet apart.
What's the next term? 2000-02-29
From Meredith O'Neill:
At this point, the whole family wants to know the answer. if possible an explanation. thanks
a sequence ?

16,37,58,89,145 ??

Weighing bales 2000-02-15
From Thinh Than:
You have 5 bales of hay. and they were weighed but they didn't weigh them individually, they were weighed in pairs. The pairs were 1&2, 1&3, 1&4, 1&5, 2&3, 2&4, 2&5, and so on. The weights of the pairs were 80,82,83,84,85,86,87,88,90, and 91. Can you tell me how much the bales weigh individually.
Euclidean Math puzzle 2000-01-24
From Margaret Matthews:

(Check out this web-site: Simeon's Triangle Puzzle )

I have tried to figure out how this could be, because everything I know about it tells me it can't be. However, I can't seem to make it NOT work.

Two right angle triangles. They are each cut up into four identical pieces. In the first, all the pieces fit together so that there are NO empty spaces; in the second, presumed to be identical in size to the first, the pieces are slightly rearranged, and now, there IS a space in the triangle.

Answered by Patrick Maidorn and Claude Tardif.
From Nick:
There are 5 lily pads and 4 frogs, 2 Red and 2 Green, how many moves does it take for them to swap sides?

I have a formula which will tell you how many moves it will take with different total numbers of frogs, it is [(F*F)/4]+F Where F is the number of red frogs add the number of Green frogs. This formula only works with numbers of frogs that are the same on each side. What I would like to know is why this formula works and why you have to divide it by 4?

An unbelievable story 2000-01-17
From Melissa:
good morning-i am taking a course "math for elementary teachers" and i have a take home problem that i really need help on. here is the question
-the million dollar problem
a recent item in the newspaper described a robbery in which the robber had held up a local bank for 1 million dollars in small bills, had the tellers put the money in a briefcase which he gave them, and fled the scene on foot. is this story believable? explain your answer!

A three digit number 2000-01-13
From Manali Shah:
My son is in 5th grade, he has a math problem. There is three digit number, which is greater than 500, can be divided by 7,9 and 11, but cannot be divided by 2,4,6, and 5.
How many coins is one calculator? 2000-01-09
From Mandy Brockmann:
Tom weighed 1 pen and his calculator with 4 coins. Then he weighed his calculator and 3 pens with 12 coins. How many coins is one calculator?
Cutting a carpet 1999-12-15
From Heather:
A rectanglular piece of carpeting is 90 inches long and 90 inches wide. How can the carpet be cut into two pieces of equal sides and shape to cover an area of 100inches? There can only be one cut and no scraps. Please show me how.
Passing trains 1999-12-10
From Nancy:
Two trains, each of 80 cars, must pass on a single track which has a deadend siding. How can they pass if the siding can only hold a locomotive and 40 cars?

I do not understand this...help. It will be due monday. I thought it would be simple if the siding could hold 80 cars.

Camels and bananas 1999-12-02
From Marie Rich:
Corey Camel's harvest, worth its weight in gold, consists of 3000 bananas. The market place where the stash can be cashed in is 1000 miles away. However, Corey must walk to the market, and can only carry up to 1000 bananas at a time. Furthermore, being a camel, Corey eats one banana during each and every mile she walks (so Corey can never walk anywhere without bananas). How many bananas can Corey get to the market?
A goofy clock 1999-11-20
From Kate:
While repairing a watch, a jeweler removed the hands and inadvertently replaced the hour hand on the min. spindle and vice versa. he set the hands to read 2:00pm, which was the correct local time when I picked up the watch. A few minutes later, I noticed that the hands were taking goofy positions. What was the first time thereafter that the watch would show the correct local time?
Selecting some players 1999-11-20
From Korbin Brown:
Roger Craig, during his term as team manager of the San Francisco Giants, received a strange communication from the team general manager, Al Rosen. Mr. Rosen told him to select 25 players according to this formula: 1/2 of the team had to be outfielders and infielders 1/4 of the team had to be starting pitchers 1/6 of the team had to be relief pitchers 1/8 of the team had to be catchers Roger was a bit confused by Al's request, yet complied anyway. How did he do it?
Mean, median and mode 1999-11-06
From Rick:
I have five number places and the mean and median are both "0". The mode is greater than the mean. The sum of the absolute values of all of the numbers is 20. The smallest number is 4 less than the next smallest number. What are the five numbers. (negative integers can be used) All of the numbers are integers.
Cutting a board into 8 equal pieces 1999-10-21
From Brittany:
Jamie wanted a board cut into 8 equal pieces. The Lucas Lumber Co. charges 60 cents for cutting a board into 4 equal pieces. How much will it charge for cutting Jamie's board?
Find the missing numbers 1999-10-12
From Bonnie:
I must find the missing numbers and function rules

noutput
710
1220
3940
2430
16b
87c

we are totally confused can someone help

A famous mathematician 1999-10-12
From Yvette Perez:
Another way to write 3/15. Remove 0 add a line, unscramble, you have the name of a famous mathematician.
Dollar Bills 1999-09-27
From NRQT:
Why are 1999 American dollar bills worth more than 1997 American dollars bills? This has to be put into a mathematical problem???
Answered by Penny Nom and Claude Tardif.
From Yvette:
"Bobs dad is 27 yrs older then Bob. The sum of their ages 5 yrs ago was 45 yrs. How old is Bob now?"
Six toothpicks 1999-09-14
The book asks: Using 6 toothpicks represent the number 17. I am studying expressions to represent a number. ex.) (2+4)4x4=96.
Two Jugs 1999-09-14
If you have and 8 liter and a 3 liter jug and you want exactly 4 liters how do you get it if there is a water hose near by but thats all you have to get the 4 liters how do you do it ?????
Bales of hay 1999-09-13
From Ivy:
You are given 5 bales of hay. Two bales are weighed at a time, which equal the following weights:
110, 112, 113,114,115,116,117,118,120,121. What does each individual bale weigh?

2,5,8,1 yields 24 1999-09-12
From Terry Hill:
I was wondering how do I make the numbers 2,5,8,and 1 equal 24?
Four fours 1999-09-09
From Roger:
I need help with a math problem my child asked me about I guess in her 7th grade math class they were told to come up with a answer from 1-10 only using four 4's and she got stuck on the problem that needs to be equal to ten, she asked me and I couldn't help her it's sad so if you could give me the problem and and answer so i could explain it to her I would really appreciate it.
Towers of Hanoi 1999-09-03
From Jeni:
In the puzzle called the Towers of Hanoi there are three peg and you are asked to move the rings from one peg and stack them in order on another peg. You can make as many moves as you want, but each move must consist of moving exactly one ring. Moreover, no ring may be placed on top of a smaller ring. The minimum number of moves required to move n rings is 1 for 1, 3 for 2 rings, 7 for 3 rings, 15 for 4 rings, and 31 for 5 rings. Find a formula for this sequence. What is the minimum number of moves required to move 6 rings?
How to carpet a room 1999-05-31
From Appleby:
A room which is 9X12 is to be covered with carpet but the carpet has been provided in one 8X1 piece and one 10X10 piece. The larger piece is to be cut into two pieces so that the room can be covered in carpet.
Three Daughters 1999-05-18
From Norm Campbell:
I recently received a beat up copy of the three daughters question. I have only some of the question. It ends after the statement "the oldest one looks....... It does not finish. Is there any chance that someone can finish it off for me?
Answered by Rick Seaman and Harley Weston.
A Puzzle 1998-10-27
From Bruce Bragnu:
We are trying to solve what SHOULD BE a simple 7th grade problem and have run into a wall.
It is:
ABCD
ABCD
ABCD
ABCD
-------
EBEA

It is an addition problem. Each particular letter represents the same digit. We are looking for what number "B" represents. We have tried a multitude of solutions and have come up empty.

Tangrams 1998-02-24
From Allison:
Do you know the story behind the tangram? I know that it is a Chinese puzzle about 200 years old. If there is a story about its creation, I would love to share it with my 7th graders. Thanks.
Answered by Diane Hanson and Penny Nom.
Pentominoes 1996-11-14
From Sam Maraldo:
What is a pentominoe? I need to understand the concept and how/why it is used?
Will this always yield a palindrome? 1996-08-28
From Andy Golden:
My friend Justin Skywatcher, said that when his children were in 6th grade, they were taught that if you take any number, reverse it and add the two together, a palindrome will result. If not, continue performing the above operations, and a palindrome will eventually result. Will this always yield a palindrome?
Magic Square 1995-10-20
From Marianne and Carrie:
How can an 8 by 8 square have the same area as a 5 by 13 rectangle?
Énigme 2008-04-06
From Frédérique:
Tu es dans une pièce ou il y a 3 interrupteurs reliés a 3 lumières dans une autre pièce que tu ne vois pas.Comment fais-tu pour savoir a quelle lumière chacun des interrupteurs est relié si tu ne peux aller voir dans l'autre pièce qu'une seule fois!Merci a l'avance!!!
un jardinier plantent 10 arbres 2007-09-30
From yannick:
un jardinier plantent 10 arbres.il a reussi a les disposer en formant 5 ligne de 4 arbres. retrouver une disposition possible
Illusion géométrique 2007-04-04
From Dominique:
Je n'arrive pas expliquer la modofocation de surface.