Question

Help with least common denominators?

Answer 1

Help is greatly appreciated!

Here's the question:

Wally knows that in order to add or subtract rational expressions, he has to find the least common denominator first. Unfortunately, he can not remember how to do that. Using complete sentences, explain to Wally how to find least common denominators. Make sure you clearly explain any important items to consider.

Answer 2

This question is a part of the last assignment I have in my online Algebra course. Help is greatly appreciated, and I wanna make sure I get this question right... :(

Answer 3

To find the least common denominator, simply list the multiples of each denominator (multiply by 2, 3, 4, etc. out to about 6 or seven usually works) then look for the smallest number that appears in each list.

Example: Suppose we wanted to add 1/5 + 1/6 + 1/15. We would find the least common denominator as follows…

First we list the multiples of each denominator.
Multiples of 5 are 10, 15, 20, 25, 30, 35, 40,…
Multiples of 6 are 12, 18, 24, 30, 36, 42, 48,…
Multiples of 15 are 30, 45, 60, 75, 90,….
Now, when you look at the list of multiples, you can see that 30 is the smallest number that appears in each list.
Therefore, the least common denominator of 1/5, 1/6 and 1/15 is 30.
This method works pretty good. But, adding fractions with larger numbers in the denominators it can get pretty messy.

So hold that thought for a moment, as we look at another way to find a least common denominator for adding these same fractions.

Answer 4

Thank you!!! :D

Answer 5

Like, I understand how to find the least common denominator, I just had a hard time trying to figure out how to word it.