







Converting measurements 
20070711 

From Nicole: if you have 8 oz of water how many cc: will there be. Answered by Stephen La Rocque. 





Yards per second to miles per hour 
20170511 

From Scott: If a soccer ball travels 30 yards or roughly .017 miles in 2 seconds how fast was the ball going in mph? Answered by Penny Nom. 





Gallons and cubic inches 
20161205 

From Theresa: If I did not know the cubic inches in a liquid gallon how would I find it?
In other words what is the formula for this? Answered by Penny Nom. 





The tens digit of a number is five times the unit digit 
20160519 

From sanjeev: The tens digit of a number is five times the unit digit. Find the number? Answered by Penny Nom. 





Division and units 
20150908 

From Kenneth: Hello:
Would there be a reason to divide a number without units by another number with units?
Here is an example:
35 divided by $5.00 or 35/$5.00
The answer cannot have units ($) because $5 X 7 does not equal 35 but instead $35.00.
$35.00 divided by 5 or ($35.00/5) and $35 divided by $5.00 or ($35.00/$5.00) make more sense.
I thank you for your reply. Answered by Robert Dawson. 





The units digit of a prime 
20150108 

From Patricia: Every prime number greater than 10 has a digit in the ones place that is included in which set of numbers below 1 3 7 9 or 1 3 7 or 0 2 4 5 6 8 or 1 3 5 9 Answered by Walter Whiteley. 





Rates, percentages and units 
20141230 

From Kenneth: Hello:
If percentages have no units, why are some percentages called rates, as in interest rate, or
perhaps a tax rate of 7% as an example? A rate has units of different quantities.
I thank you for your reply. Answered by Robert Dawson. 





Water usage in Ames 
20140829 

From Abigail: The City of Ames water treatment plant treats 7 million gallons of water per day on
average to meet water demands. Hypothetically, if water is withdrawn from a
groundwater system with an area of 51.6 square miles
(approximate area of Ames and surrounding area),
what is the depth of water in inches that would have to be added to
the groundwater system annually to replace the water that is withdrawn by the city? Answered by Penny Nom. 





Fractions and units 
20140428 

From Aaron: I can't do this math problem. please help.
Find 200m over 1 min times 60 min over 1 hr times 1 km over 1000 m.
the choices are a. 300 km/hr b. 12 km/hr c. 300 m/hr and d. 12 m/hr Answered by Penny Nom. 





Units digit 
20140103 

From gracie: 9^23 units digit Answered by Penny Nom. 





The units digit 
20120911 

From Shaunice: Simplify each of the following expressions and determine what the last
digit would be.
a. (24^15) 4 Answered by Penny Nom. 





The units digit of a prime number 
20111122 

From Mike: Every prime number larger than 10 has a digit in the ones place that is included in which set of numbers below?
A. 1,3,7,9
B. 1,3,5,9
C. 0,2,4,5,6,8
D. 1,3,7 Answered by Penny Nom. 





Ratios 
20111017 

From Kenneth: Can you think of a ratio that has units that have not canceled out?
Do not use a rate as an example, for example miles per hour.
Would the following make sense? What is the book to student ratio in
a classroom with 20 students and 15 books? Student to book ratio of
20 students to 15 books or (4 students):(3 books). Answered by Penny Nom. 





The dimension of the box in centimetres 
20110827 

From Eliza: Find the dimension of the box in centimetres. Then find its volume in cubic centimeters.
The box is 0.7m (l) 0.4 (h) 0.2 (w) Answered by Penny Nom. 





The mass of a metal box 
20110311 

From Pamela: A metal block has the dimensions of 3.16 inches wide, 2.15 inches
high, 4.98 inches long. What is the volume of the block in cm^3?
What is the block's mass if the metal has a density of 5.89g/cm^3. Answered by Robert Dawson. 





A two digit number 
20110301 

From jhoanna: the sum of the digits of a two digit number is 10. The value of the number is 16 times the units digit.Find the number. Answered by Penny Nom. 





Ratios and proportions with mixed units 
20100513 

From Kenneth: Is it incorrect to have a proportion with numbers containing units that are not the same on both sides of the equal sign?
Here is an example: $0.07/$1.00 = ?/$0.89 is okay, but if I add a different unit (20 ounces) to one side of the equal sign but not the same unit to the other, is the proportion incorrect?
$0.07/$1.00 = ?/$0.89/20 ounces.
In order to determine the missing amount, the calculation becomes ($0.07/$1.00)/$0.89/20 ounces = $?, but is this proportion correct with the units as they are?
Two dollarunits cancel leaving dollar/ounces equals $?/ounces, but is this correct? Answered by Robert Dawson. 





Metric prefixes 
20100316 

From ali: How do you convert zectometres to yoctometres Answered by Robert Dawson. 





Square poles 
20100216 

From Steve: If 1 pole=16.5', and you have an area that is 146 sq. poles, how many sqaure feet would you have?
I calculate that to be 146(16.5)X146(16.5)=5,803,281 sq. feet Is that correct? I am told I need to divide by 146, which makes the answer 39,748. I do not understand why I need to divide by 146.... Answered by Penny Nom. 





What time did susan go to bed? 
20100214 

From Sophia: Susan woke up at 7:42 Am to get ready for school. She slept for 10 and 1/3 hours. What time did she go to bed? Answered by Stephen La Rocque. 





How do you convert cents/mile to dollars / hour? 
20090826 

From seanna: how do you convert cents/mile to dollars / hour Answered by Penny Nom. 





Units digit 
20090723 

From Jyll: How do solve for the units digit? And that, what is the units digit of the first 1000 prime numbers? Answered by Robert Dawson. 





Unit Conversion for Force and Mass 
20090508 

From Ray: Good Day! I was confused about lbm and lbf and slug. I knew that lbm is a unit
for mass and lbf is a unit for weight. my problem is some books follow this
relationship where lbf=(lbm times the gravitational pull) which is 32.2 ft/(s^2)
while other books treat lbm=lbf. other books also treat lbm=(lbf times 32.2)...
which is correct?
Is 1kg=2.205 lbm or 1kg=2.205lbf?
Is 1BTU=778.16 lbfft or 1BTU=778.16 lbmft?
what is the relationship of slug on these two, lbm and lbf? Answered by Janice Cotcher. 





Miles per hour and feet per second 
20090422 

From mary: A car traveling at 60 miles per hour, how many feet per second has it traveled? Answered by Robert Dawson. 





Units digit 
20090415 

From A student: What is the unit digit of 47 to the 43rd power? Please answer as soon as possible. Thank you. Answered by Stephen La Rocque. 





Milliliters of oxygen in your lungs 
20090320 

From Leandrea: if you have 3 liters of air in your lungs and 2/10 of that is oxygen, how many milliliters of oxygen are in your lungs? Answered by Penny Nom. 





The units digit of 2^95 
20090318 

From Sharvon: what is the units digit of 2^95 Answered by Robert Dawson. 





36cm to the second power divide 10cm 
20090226 

From val: 36cm to the second power divide 10cn Answered by Penny Nom. 





Can you convert numbers with units to percents? 
20090212 

From Kenneth: To change a number to a percent, move the decimal two places to the right and add a percent sign.
For example, 0.35875 = 35.875%.
If the number has a dollar sign or some other kind of unit, for example, pounds, feet, etc. how is the number converted to a percentage.
For example, change $0.35875 and 0.75 lbs. to a percentage. How is this done. I have never seen $35.875% or 75 lbs.% before. Answered by Robert Dawson and Harley Weston. 





The units digit is 5 
20090202 

From Ray: the number that when squared the units digit is 5 Answered by Penny Nom. 





The tens digit of 0! + 1! + 2! + 3! + 4! .............+9999! + 10000! 
20090123 

From Kaylyn: determine the tens digit for the expression:
0! + 1! + 2! + 3! + 4! .............+9999! + 10000! Answered by Robert Dawson and Penny Nom. 





The 2 rightmost digits 
20081218 

From Peter: Is there a pattern for the 2 rightmost digits of a power? For example, one problem for a math competition was what are the 2 rightmost digits of 3^1993? Answered by Robert Dawson and Victoria West. 





Three equal ratios 
20080926 

From Jodi: For the ratio given, find three equal ratios: 2 miles/8 minutes Answered by Penny Nom. 





Sample variance: inches to centimeters 
20080922 

From Anita: The average height of a sample of basketball players is 6 feet, 2 inches or 74 inches.
The standard deviation of this sample of players is 4 inches. If each person's height were to be multiplied by 2.54, what would be the value of the resulting sample variance? Answered by Harley Weston. 





3 miles in 6 seconds 
20080905 

From Grant: if a rocket sled is traveling 3 miles in 6 seconds, how fast is it going in miles per hour? Answered by Harley Weston. 





How many litres of rain is this? 
20080901 

From Todd: If i have 10mls of rain over one square metre how many litres would I
and how do I do the maths for this? Answered by Penny Nom. 





Converting centimetres to metres 
20080821 

From walter: how do you convert the smaller unit to a decimal of the larger unit and then solve
17 m  130 cm Answered by Penny Nom. 





How many decimeters are in a meter? 
20080811 

From Julia: How many decimeters are in a meter? Answered by Penny Nom. 





The units digit of (7*3)^21 
20080716 

From surender: what will be the unit digit of (7*3)^21?plz give me method 2 calculate such problems.thank you. Answered by Penny Nom. 





Units digit 
20080702 

From seemachauhan: How to find unit digit of various numbers and what are unit digits? Answered by Penny Nom. 





How much seed do I need per plot? 
20080513 

From Jaye: The plot size is 5 m X 2 m. The seeding rate is 12Kg/ha. How much seed do I need per plot? I have failed to get a proper answer.
Thank you. Answered by Penny Nom. 





Converting metric density 
20080428 

From Hilary: 10g/100ml=?g/?l
52g/100ml=?g/?l
65g/100ml=?g/?l
100g/100ml=?g/?l
137g/100ml=?g/?l
0.15g/100ml=?g/?l Answered by Penny Nom. 





Crosssectional area of a fire hose 
20080127 

From Tom: My question is this I know the equations for the final answer but the book skips how to get to one section of the equation. Q=(a)(v)
A= The crosssectional area of the conduit in square feet (ft2). So if you have a 5 inch hose how do they get A=0.136 ft2 ? And I know the velocity already v= velocity in ft per second. Answered by Stephen La Rocque. 





A fraction comprised as 2 numbers having the same units 
20080127 

From nancy: term=a fraction comprised as 2 numbers having the same units Answered by Stephen La Rocque and Harley Weston. 





How many meters/kilometers/millimeters would that be? 
20080117 

From chantal: if a ocean/lake/river is 250meters from where you are, how long would it take to get to shore? how many meters/kilometers/millimeters would that be? Answered by Penny Nom. 





Percentage and units 
20080115 

From Kenneth: Hello:
If the sales tax on merchandise sold in stores is 6%. The item is
multiplied by the sales tax of 6%. For example, the sales tax on
pencils worth $1.00 is 6% X $1.00 is $0.06 or 6 cents plus $1.00 for
a total of $1.06.
1. If the tax is 6%/$1.00, why doesn't the dollar sign as a unit cancel
after the multiplication?
Isn't it 6%/$1.00 X $1.00 or whatever the dollar amount is?
The dollar signs should cancel, but they do not.
2. If percentages are unitless, is there a reason? Answered by Harley Weston. 





Units digit 
20080111 

From Robin: hello  my question is:
what is the units digit of (13) to 4; (17) to 2 and (29) to 3
[(13)4(17)2(29)3]
(possible answers: 9 or 7 or 5 or 3 or 1) Answered by Penny Nom. 





Changing units and sizes of things 
20071108 

From Carol: volume of cube = 216 cubic inches how do I calculate cubic feet and calculate its surface area in square feet.
a rectangular box has dimensions of 3 x 6 x 15 how do I calculate surface area in square yards and calculate volume in cubic inches. if I double the dimensions how does it affect the volume Answered by Stephen La Rocque. 





The sum of the ones 
20071029 

From Hangsun: When 2 two digit numbers are added what is the greatest possible sum of the ones? Answered by Penny Nom. 





Tens and ones 
20070916 

From julia: My son has come home with a math question "what i know about 10s and 1s" we're totally stumped any information you can provide would be greatly appreciated Answered by Harley Weston. 





Counting stitches and changing units 
20070828 

From Lim: Jack is making stuffed toys. Each toy needs 360 stitches. Ten stitches take 15 seconds.One toy needs
57cm of cotton for stitches. How many centimetres of cotton does Jack use in an hour? Answered by Stephen La Rocque. 





Which is more, 1.25 grams or 4.7 ml? 
20070822 

From jenni: Which is more? 1.25 grams or 4.7 ml Answered by Penny Nom. 





The units digit of 23^45 + 67^89 
20070816 

From Christopher: What is the units digit of 23 to the 45th power plus 67 to the 89th power? Answered by Stephen La Rocque. 





Converting dollars to gallons 
20070612 

From Cynthia: How do I solve this problem?
If a family uses .20 per 100 gallon of water. How many gallons would
$10.00 cost, divided amoung 3 people?
Thanks, Cynthia Answered by Stephen La Rocque. 





Volume of a brewer's sphere 
20070604 

From Edward: A Brewer's Sphere that has a 9' Dia. Holds how much Brew? How many 40oz bottles will be needed to hold his batch of Brew? Answered by Stephen La Rocque. 





Converting speeds 
20070510 

From jason: A boy runs 36 metres in 6.50 seconds.How fast is he going in miles per hour Answered by Stephen La Rocque. 





Converting from mm to cm 
20070508 

From Amanda: How do you convert mm into centimeters? Answered by Gabriel Potter and Steve La Rocque. 





Conversions 
20070209 

From Donna: Hi! I hope you can help me... What is the cost of 10 grams platinum if one ounce = $1200 (troy weight)? I REALLY appreciate your help. Can you please send me the formula to figure it out too? Thank You! Donna :) Answered by Stephen La Rocque. 





The units digit of 9^2006 + 3^2006 
20070130 

From Ryan: What is the units digit of the sum of 9^2006 and 3^2006 Answered by Penny Nom. 





how do i find ratio of 1,000mm to 5m 
20070118 

From Harry: how do i find ratio of 1,000mm to 5m Answered by Paul Betts. 





The units digit 
20070109 

From Tyrone: This may be a dumb question, but what is the unit digit of two digits, eg: 62 or 13 or 45. Answered by Steve La Rocque and Diane Hanson. 





The units digit of 1^5 + 2^5 + ... + 2006^5 
20061114 

From Lana: Compute the unit's digit of : 1 to the power of 5 + 2 to the power of 5 + 3 to the power of 5 + 4 to the power of 5 + 5 to the power of 5 + 6 to the power of 5 + ... + 2006 to the power of 5 . Answered by Stephen La Rocque and Penny Nom. 





3.253 cubic meters of water 
20061031 

From Elaine: a tank full of water that has a volume of 3.253 cubic meters would have a mass of? Answered by Penny Nom. 





The units digit of 12^40 
20061008 

From Lana: FIND THE UNITS DIGIT OF 12 TO THE POWER OF 40. Answered by Penny Nom. 





Metric Conversions 
20060902 

From Patricia: I have a new difficulty, metric conversion when it involves the prefixes. Some problems I need help with are: Answered by Stephen La Rocque. 





Ounces of water to grams 
20060716 

From Liza: How many grams is in 10 ounces? I'm asking this question because i just bought a sea monkey and it says add 10 ounces of water and I don't know what that means. I have asked my parents but neither of them know. Answered by Stephen La Rocque. 





What is the height of the pot? 
20060310 

From Michelle: If a pot is 11 inches in diameter and holds 5.8 litres what is the height of the pot?  assuming it is a cylinder. Answered by Stephen La Rocque. 





The units digit 
20060305 

From Taran: My teacher asked: What is the unit's digit in the product 5 X 10 X 15 X 20 X 25? What is a "unit's digit", what are they asking for? Answered by Penny Nom. 





Volume 
20060302 

From Irene: how do you find the volume in cubic units. i need the basic formula to help my child. Answered by Penny Nom. 





Converting units 
20060121 

From A student: How can you solve a measurement problem by changing it to a fraction of the new unit that follows such as:
18 inches = yard
40 minutes =  hour
5 days =  week Answered by Penny Nom. 





what is 5'7 
20051126 

From A student: what is 5'7" inches in cm? Answered by Harley Weston. 





What is the unit's digit? 
20051004 

From Alex:
Question: What is the unit's digit of the following problem?
3^{155} + 7^{412} (3 to the 155th power + 7 to the 412th power.)
Answered by Penny Nom. 





n^2+n1 has no divisors ending with 3 or 7 
20050908 

From Arne: at least it seems like for any integers n and k,
10k+3 and 10k+7 do not divide n²+n1
I tested this for every n from 0 to 3200 (which means same for the numbers from 3201 to 1)
could this be true, or is it just coincidence, or am I just totally wrong? Answered by Richard McIntosh. 





The units digit 
20050518 

From Gerald: Juan wrote the first 12 powers of 2. He noticed a pattern in the digits in the units places of the results. He said he could use this pattern to predict the digits for 2 to the power of 100. Answered by Penny Nom. 





Centimeters, millimeters and milliliters 
20050419 

From A student: How many milliliters in a centimeter? Answered by Penny Nom. 





Express the answer in dollars 
20050103 

From Abraham: My question on this question is if I wrote just 5280 because they say they want it in dollars, is that correct or is the only answer, 5279.61 as their answer key says? How should I have known to give it with cents? Should I give myself full credit? Answered by Harley Weston. 





The last digit of a large exponent 
20041020 

From Landon: How can one determine the last digit of a large exponent by hand. I have seen several examples of how to do this by breaking it up into smaller exponents, but is there a formula or some common things to look for? Answered by Penny Nom. 





Grams to milliliters 
20040925 

From Emily: I am trying to convert 19.5g into mL assuming that it's water; density=1g/mL. I don't know where to begin. Answered by Penny Nom. 





The last digit of 2^28 
20040925 

From A student: I am currently enrolled in a math reasoning class and a math question I have to answer is determine the units digit in 3 28power. When I set up a table and keep cubing the numbers, I find a pattern with the last digits of the numbers that follow 1,3,9,7. My calculator gets to about the 19th power, and then I get an error. If I continued the pattern, would the units digit then be the last digit of 3 28th power, which would be a 7? Please let me know if I am solving this correctly and what a unit's digit actually is. Answered by Penny Nom. 





Division with and without units 
20040917 

From Kenneth: What does it indicate when the divisor has units (dollars) but not the dividend, as in 500/$10.00 or 500 is divided by $10.00?
Are the units understood to be there? Does 500/$10.00 make sense? Answered by Penny Nom. 





The units digit of 4^478 
20040306 

From Elizabeth: What is the units digit of 4^{478}? Answered by Penny Nom. 





The units digit of 57 to the 28th power 
20030901 

From Maria:
If 57 is raised to the 28th power, what must be the units digit in the result? If you raise 7 to the 500th power, what is the numeral that will appear in the units digit position? Answered by Penny Nom. 





An inch and a millimeter 
20030621 

From Greg: The conversion factor for inches to millimeters 25.4 It strikes me as very odd that it's not some infinite decimal. I could understand this if one system was derived from the other but as I understand it they were derived independently. Is the conversion 25.4 or 25.4000XXXXXXX? If it's just 25.4 then how did that happen? Answered by Harley Weston. 





The metric and Imperial systems 
20030608 

From Ashlee: i am a year 8 student, and i am doing my Maths talent quest on the Metric and Imperial number system.
i was wondering, where did the 2 systems orginate and if possible, a little bit or information.
I also need to know the conversions of ounce, foot, mile..etc..from imperial to metric. Answered by Penny Nom. 





The units digit of 2 to the power of 31921 
20021218 

From A student: If 2 to the power of 31921 is multiplied out, what will be the units digit? Answered by Penny Nom. 





Units 
20021212 

From Debbie: The general equation for a parabola is y = ax^{ 2} + bx + c, where a, b, c are constants. What are the units of each constant if y and x are in meters? Answered by Penny Nom. 





Kilometers to miles 
20021009 

From A student: how many miles are in 16 kilometers? Answered by Leeanne Boehm. 





Gallons in a cylindrical tube 
20020821 

From Heidi: IF I HAVE A 12" DIA TUBE WITH 1/4" WALL AND 72" IN LENGTH HOW MANY GALLONS OF WATER WILL THIS HOLD Answered by Penny Nom. 





Conversion of units 
20020429 

From Matt: I am having trouble finding a workable equation for the following problem, particularly the conversion of two systems of measurement. The question states that there are 27 grams of salt in a kilogram of seawater. And it asks how many tonnes (1 tonne = 1000 kilograms) of salt are there in one cubic kilometer of ocean. It also says that the density of seawater is 1.1 g/cm3. What is the equation and how do I figure out how many kilograms there are in a cubic kilometre? Answered by Harley Weston. 





Number conversions and averages 
20020203 

From A student: A table has the measurements of 1.6m by 2m, how much material is needed to cover table? I converted to cm then multiplied but got an answer of 32000cm ,so I divide by 100 to get to metres  the answer was 320 which I know is wrong  please explain!! Also I need to explain in my own words what an 'average' is and I am struggling. Answered by Penny Nom. 





Metric units 
20011025 

From Kelly: i am helping my kids out with school work and don't remember meters,centimeters decimeters and all those. We have to change meters into cm.....and so on..........is there a place on the web to look for some kind of help in these questions Answered by Penny Nom. 





Milliters and grams 
20010920 

From Bettyjo: 500 ml is what in grams Answered by Pnny Nom. 





How many acres are in a square mile? 
20010504 

From Terri: How many acres are in a square mile? Answered by Judi McDonald. 





Conversions 
20010124 

From Tanya: I have 2 questions  covert 628 kilometers to miles.(round off your answer to two decimal places.)
 a new clerk in your office is to earn $200 per week. If she works 30.5 hours each week, what is her hourly rate? (round off your answer to the nearest hundreth, that is, to the nearest cent.)
Answered by Penny Nom. 





Cubic yards and cubic feet 
20000826 

From Rhonda: have 2.47 cubic yards. what could the dimensions, in feet, be to equal this? Answered by Penny Nom. 





The units digit of 3 to the 58th power 
20000510 

From Kylie Mcalpine: the questions we have been asked are what is the units digit of the following: a) 3^{58} b) 23^{58} c) 17^{31} and the harder question of: what is the units digit of the following sum: 13^{841} + 17^{508} + 24^{617} = ??????? Answered by Paul Betts and Penny Nom. 





Conversions 
20000423 

From Tara: 750 lbs = ___ tons How do I figure this out!? I know that 1 ton is 2000 lbs, how do I figure out this answer? Answered by Penny Nom. 





Circumference = Area 
20000419 

From Scot George: The area and circumference of a circle has the same measurement. Find the radius. Answered by Chris Fisher. 





Unit conversions 
19990420 

From Deanna: My question has to do with unit conversions with English and metric systems. I need to know how to use conversion factors with powers of 10. Which way do i move my decimal point. ex. .48kl to liters. Thank you. Answered by Jack LeSage. 





Metric Conversion 
19990307 

From TDestra: Please help to answer this question: Is a cubic centimeter equivalent to milligrams or milliliters, and how many? Also, is it a liquid measure? Answered by Penny Nom. 





Les tableaux de conversions 
20010503 

From JeanJacques: Sur quel site est il possible de trouver tous les tableaux de conversions de mètres,kg,litre,m2,m3 Quelle est la relation entre les m^{3} et les litres 1 m^{3} = 1000 litres = 1000 kg? Answered by Claude Tardif. 

