And just as an added explanation, if the amount of cups is a fraction, (like 1 and 2/3 cups).... YOu already know 1 cup is 8 oz. To find two thirds cups, you would want to find out how many ouces were a third, first ( 8oz divided by 3 (a third) = 2.66 oz) Then multiply times 2 (because you want to find out TWO thirds) (2.66 oz times 2 = 5.32 oz.)
So..
The 1 cup = 8oz. (right, we knew that already)
the 2/3 cup = 5.32 oz.
The total of 1 and 2/3 cups in ounces is 13.32 (8+5.32= 13.32)
Since the .32 is about a third, you can assume 13 and 1/3 ounces is very close to exactly equivalent.
So..
The 1 cup = 8oz. (right, we knew that already)
the 2/3 cup = 5.32 oz.
The total of 1 and 2/3 cups in ounces is 13.32 (8+5.32= 13.32)
Since the .32 is about a third, you can assume 13 and 1/3 ounces is very close to exactly equivalent.