Math
posted by Alex L. .
I have to find the prime factorization of each number and write down the answers with exponents when repeated factors appear.
eighteen, four hundred eighty, six hundred forty
Next, I need to write this fraction in lowest terms.
onehundred sixtyfive over onehundred eighty

This is not hard. Just start with 2, and divide it into the number as many times as you can. Then try 3,5,7,... for all primes up to sqrt(N). Why stop there? because if one factis greater than sqrt(N), the other factor will be less.
18
2*9
2*3*3 = 2*3^2
480
2*240
2*2*120
2*2*2*60
2*2*2*2*30
2^5 * 15
2^5 * 3 * 5
640
2^6 * 10
2^7 * 5
165/180
3*5*11/2*2*3*3*5
11/2*2*3
11/12