3 : In order to subtract the fractions, you need to find a common denominator. The common denominator can be found by multiplying the two denominators together.
4 x 8 = 32
4 : Rewrite each fraction as an equivalent fraction with a denominator of 32.
4/8 —> (4 x 4)/(8 x 4) —> 16/32 ¾ —> (3 x 8)/(4 x 8) —> 24/32
5 : Subtract the numerators. Simplify the answer if needed. 16/32 - 24/32 16 - 24 = -8 -8/32 —> (-8/4)/(32/4) —> -2/4 -2/4 —> (-2/2)/(4/2) —> - ½