I am ready to make pancakes. Each individual pack needs 2/3 cup of milk but I only have a 3/4 measuring cup. What do I do?

(2/3) / (3/4) = 8/9

So, you could estimate. Fill the 3/4 cup almost full. For pancakes, that should be close enough.

Or, since 8 cupfuls will measure 6 cups of mile, use 9 packs of mix, which need 6 cups of milk.

Feed lots of people.