My Math Forum  

Go Back   My Math Forum > High School Math Forum > Elementary Math

Elementary Math Fractions, Percentages, Word Problems, Equations, Inequations, Factorization, Expansion

Thanks Tree2Thanks
  • 2 Post By Denis
LinkBack Thread Tools Display Modes
April 27th, 2018, 08:15 AM   #1
Joined: Apr 2018
From: United States

Posts: 1
Thanks: 0

Factoring large odd/uneven numbers?

I fell into this problem when trying to figure out a way to subtract fractions with big uneven denominators, and am stuck. How do we use prime factorization for numbers like this?

2/57 - 9/67

Is it okay if you get fractions in prime factorization? What should I do? Thank you!
Mari13 is offline  
April 27th, 2018, 08:32 AM   #2
Math Team
Joined: Oct 2011
From: Ottawa Ontario, Canada

Posts: 12,892
Thanks: 882

a/u - b/v = (av - bu) / (uv)
Thanks from topsquark and Jsss
Denis is offline  
April 28th, 2018, 11:47 AM   #3
Senior Member
Joined: May 2016
From: USA

Posts: 1,084
Thanks: 446

As Denis implies, you may have been taught to find the least common denominator when adding or subtracting fractions, but that is not at all necessary. What is necessary is to find a common denominator. And that is most simply done by finding the product of the denominators.

EDIT: In the case of your example, where denominators are both prime numbers and cannot be factored, their product is the least common denominator, but such a product will always be a common denominator.

Last edited by JeffM1; April 28th, 2018 at 12:07 PM.
JeffM1 is offline  

  My Math Forum > High School Math Forum > Elementary Math

factoring, large, numbers, odd or uneven

Thread Tools
Display Modes

Similar Threads
Thread Thread Starter Forum Replies Last Post
ratios with large numbers marf New Users 1 June 10th, 2017 11:56 AM
large numbers? jk12 Math 0 May 13th, 2017 04:45 PM
Are large numbers definable? jk12 Math 42 May 18th, 2015 02:14 PM
Law of Large Numbers and Expected Value Tomi Advanced Statistics 0 February 12th, 2014 12:00 PM
Law of Large Numbers and the Expected Value jimmy Advanced Statistics 4 July 18th, 2012 12:23 PM

Copyright © 2018 My Math Forum. All rights reserved.