Note, this is not a homework problem, as I'm not even in college. I just had a quick question. I know the formulas to do things such as "How many ways could you choose 5 balls from a tub of yellow, red, and blue colored balls?" (where you envision in this case, a tub where there's more than 5 yellow, more than 5 red, and more than 5 blue) But what if you have a situation where say, there's more than 5 red and more than 5 blue, but maybe there's only 3 yellow? So there's a "limit" on one of your repetition groups. When you run in to situations like this, do you have to break things down in to disjoint sets?