Just wanted to know if they're used outside of math class for anything practical?
Suppose that a class of 20 goes in to have group pictures made.
They may have four groups of five made to fit on a page in an annual.
How many ways can this be done?
This becomes important if certain groups are made to be together.
Suppose there are only five minority members. What is the probability that in a random selection that all five are grouped together?