There are numerous ways he could do this, but for example, let's take two ways which are common:
1) He could take the 1/2 cup twice which equals 1, and then he could measure 6 of 1/8 cups which would be 6/8 or 3/4.
2) Way number two could be if he took the 1/2 four times, which would give him 2, and then he could remove 2 1/8 cups out of the 2 which would give him 1 3/4.
