Question

A batch of cookies calls for 3/4 cup of flour. You want to make 1 1/2 of a batch. How much flour do you need?

Answer 1

3/4 * 1 1/2 = 3/4 * 3/2 = 9/8 or 1 1/8 cups
or, as a proportion
x/(1 1/2) = (3/4) / 1

Answer 2

How did you go from 9/8 to 1 1/8?

Answer 3

1 1/2 = 3/2
when multiplying fraction you multiply straight across.
3/4 * 3/2 = 9/8