Note: My children are 4th grade and below.
I found out that the easiest way to do this is to multiply the two denominator. Let's say you have 1/2-1/4. Multiply 2x4 and you get 8. Re-write the fraction for 1/2 as 4/8, because there are 4/8 in 1/2, and 1/4 as 2/8, because there are 2/8 in 1/4. Then 4/8-2/8=2/8 or you can write it in simplest form as 1/4.
This is the very basic I can do so far. My 4th grader is also did some with whole numbers with different denominator, however the process is the same. The whole number doesn't change, only the fraction.
Please remember this is only the basic. Hopefully when we do the advance lesson I can still remember the basic way to do this...whew.
7 months ago