Lesson: Operations with Fractions

Comment on Operations with Fractions



So right on the money!
greenlight-admin's picture

Ha! Awful indeed! (aside: Omar is referring to 7:14 in the video)


Are the official GRE paper test reinforcement activity questions from an older version paper test or from the version that has significant overlap with the 2 powerprep practice tests?
greenlight-admin's picture

I believe that the questions in the paper test do not overlap with the PowerPrep practice tests.

The last 3 links don't go to any specific problems. It just takes you to the homepage of themathpage.com
greenlight-admin's picture

Thanks for pointing that out!

Looks like TheMathPage.com changed the urls of all its pages.
I've updated all of the links above, and I'll try to get to the rest of the links (throughout this site) this upcoming week.

Cheers and thanks again,

What about Addition and subtraction in mixed fractions ?
greenlight-admin's picture

Good question. One option is to convert both to entire fractions, and then perform the calculations.


Hi Brent,

When trying to find the common denominator for 1/3 + 1/6, isnt the common number that divides both 3 and 6 are 3?

I mean 3 is a multiple of both 3 and 6 right?
greenlight-admin's picture

3 is the GREATEST COMMON DIVISOR of 3 and 6.
When it comes to adding or subtracting fractions, we want to find the LOWEST COMMON DENOMINATOR, which is the same as finding the LEAST COMMON MULTIPLE.

Sum of multiples of 3 are: 3, 6, 9, 12, 15, 18, 21,....
Sum of multiples of 6 are: 6, 12, 18, 24,30,....
(Aside: Notice that 3 is not a multiple of 6)

Among the above multiples, the SMALLEST multiple they have in COMMON is 6.

When cross simplifying, is it ok to only simplify one set, or do you have to do both?
EX: 5/25 * 5/3
You can 5 & 25, but you can't simplify 5 & 3. So if I simplified 5 & 25 without simplifying 5 & 3, would that mess up my answer?
greenlight-admin's picture

No, you need not simplify both pairs of values.
For example, 7/12 x 24/13 becomes 7/1 x 2/13 after simplifying.
Likewise, 25/8 x 11/15 becomes 5/8 x 11/3 after simplifying.

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