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prime factor

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Factors 2017-08-16
From Gemma:
Why do 315 and 525 have the same number of factors?
Answered by Penny Nom.
The product of a 2-digit number and a 3-digit number 2015-02-06
From Nathaniel:
The product of a 2-digit number and a 3-digit number is about 50 000 what are the products
Answered by Penny Nom.
Prime factorization in exponent form 2014-10-31
From Emma:
I need to find out how to make a prime factorization of 120 in exponential form.
Answered by Penny Nom.
Sieve of Eratosthenes 2014-10-03
From Hope:
using Sieve of Eratosthenes to determine for in instance prime numbers between 1 to 200, to what nth number should i stop?, 4th, which is 11 or what?
Answered by Robert Dawson.
Prime factorization 2014-02-06
From Kadeejah:
Write the prime factorization of 37 in exponential form
Answered by Penny Nom.
What is the prime factor form of 7/5? 2012-04-17
From David:
What is the prime factor form of 7/5
Answered by Robert Dawson.
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.

Answered by Penny Nom.
Exponential form 2009-08-31
From cecil:
what is the exponent form 564000?
Answered by Stephen La Rocque and Harley Weston.
The prime factorization of one billion 2008-11-02
From Alta:
The prime factorization of 1000 is 2 cubed times 5 cubed. How do you write the prime factorization of one billion using exponents?
Answered by Penny Nom.
Prime factorization 2008-10-19
From nick:
while im doing prime factorization for one number and it cant be divided 2,3 or five so what next?
Answered by Penny Nom.
Product of Two-Digit Numbers 2008-07-31
From pete:
The number 4641 can be expressed as the product of two two-digit whole numbers. What is the sum of these two numbers?
Answered by Janice Cotcher.
The square root of (18*n*34) 2008-07-01
From Peter:
What is the least possible positive integer-value of n such that square root(18*n*34) is an integer?
Answered by Penny Nom.
Prime factors 2008-05-21
From john:
the first 5 prime numbers are 2,3,5,7,11. which is the smallest number that has these prime factors.
Answered by Stephen La Rocque.
13 year and 17 year locusts 2007-10-12
From stefan:
how many years pass between the years when both 13 year and 17 year locusts are out at the same time?
Answered by Penny Nom.
Prime factors in exponential form 2007-09-06
From Michelle:
how would you write this: factor 48 as a product of primes written in exponential form
Answered by Stephen La Rocque.
If the product of A,B,C is 15834, what is A+B+C? 2007-03-10
From rachel:
if the product of A,B,C is 15834, what is A+B+C?
Answered by Penny Nom.
The greatest common factor of two numbers 2006-07-16
From Fadwa:
What is the greatest common factor(GCF) of the following algebraic expressions? 1680 and 6048
Answered by Stephen La Rocque.
How many numbers are relatively prime with 250? 2006-04-19
From David:
How many positive integers less than or equal to 250 are relatively prime with 250?
Answered by Stephen La Rocque.
How many divisors does the number 138600 have? 2006-02-08
From Joe:
How many divisors does the number 138600 have?
Answered by Steve La Rocque and Penny Nom.
LCM 2005-12-12
From Alex:
what is the LCM of 210 and 54 and the LCM of 42 and 126
Answered by Penny Nom.
252 x ? is a cube 2004-12-22
From Andrea:
What is the smallest positive interger by which 252 can be multipled so the result is a perfect cubed?
Answered by Penny Nom.
an integer with three factors 2004-08-03
From A student:
What is the probability that a randomly chosen 3 digit number has exactly 3 factors
Answered by Penny Nom.
Making a square 2003-09-07
From A student:
if I am given any number (say 80 for example), how may I determine the smallest whole number integer which when multipled by it will yield a square number ? In other words if I express this as: 80İ*İnİ=İsquareİnumber, what is the least value of n which will yield a square.
Answered by Penny Nom.
1575 2003-03-13
From Sharyn:
find 6 integers that when multiplied with each other equal +1575 and when the same integers are added together equal zero. there are more positives than negatives and one of the numbers is a double digit between 10 and 20
Answered by Penny Nom.
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?
Answered by Penny Nom.
Primes and square roots 2001-06-14
From Paul:
I have a bit of a math problem. It has to do with determining if a very large number is a prime. One method entails dividing the number by every smaller prime number. If any divide into it, it's not a prime. This would be a big job if the number was something like 400 digits long. Another way I read about was to take the square root of the number and test all the primes less than its square root. The explanation went like this: "When a number is divided by another number that is greater than its square root, the result is a number smaller than the square root. For example, the square root of 36 is 6. Dividing 36 by 2, a smaller number than 6, gives 18, a number that is larger than the square root. To prove that 37 is prime it is only necessary to divide it by primes less than 6, since if it had a prime factor greater than 6, it would have to have one less than 6 as well."

I understand the explanation, up to the last sentence. I fail to see the underlying logic. Why if a prime factor exists below the square does one have to exist above the square too? The number 40 can be divided by the prime 2, a number below its square root, but no other primes can do this above its square root. Have I missed something? What's the logic here?


Answered by Claude Tardif and Penny Nom.
A zip code problem 2000-10-26
From Rob Mathis:
Find the zip code of a place in a county so that the product of it and the zip code of another place in another county of the same name, but in a different state, is an exact multiple of the number 123456789
Answered by Claude Tardif.
How many zeros? 2000-04-09
From Greg Potts:
The natural numbers 1 to 25 are multiplied together (1 x 2 x 3x..24 x 25). How many zeros are there in the product of this multiplication?
a)6 b)7 c)5 d)10 or e)4?

Answered by Harley Weston.
 
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