Consider the fractions 7/8 and 3/8. What is the sum?

You're adding right?

if so, it would be

7/8 + 3/8 = 10/8 (divide by 2) = 5/4

the reason you divide by 2 is because every fraction must be in lowest terms.

so;

10 divide by 2

-

8 divide by 2

whatever you do to the numerator (top) you must do the the denominator (bottom)