When did a cup become only three-quarters of a cup?
When recipes say to use a cup of this or that, they mean a cup of this or that. That is, they mean 250ml, which is the definition of one cup.
So why is it that food stuffs like cup-of-soups, hot-chocolate mixes, powdered punches, and the like always say to add ¾cup of water to the mix for each cup? (No, they do not provide ¼cup of mix per cup.)
It seems that in ready-made food math, 3=4!