Question

How many eighth size parts do you need to model three fourths?

Answer 1

The answer is 6/8 because 4+4=8 and 3+3=6 so it's 6/8

Answer 2

6/8=3/4:  You have to set up a proportion.  n/8=3/4.  You don't know how many out of eight, and you set it equal to 3/4.  so you cross multiply and get, 4n=28.  You algebraically solve it and get n=6.