What is three fourths minus five eighths?

First you need a common denominator:

3/4 and 5/8, the common denominator is 8. (4x2=8, 8x1=8)

Multiply both the numerator and denominator of 3/4 by 2 so that it becomes 6/8.

Now that a common denominator is established, you may subtract them with ease.

6/8 - 5/8 = 1/8.