The combination function yields the number of ways n distinct items can be chosen for k spots, when the order in which they are chosen does not matter--that is, choosing ABCDE is equivalent to choosing BAEDC. In other words, we use the combination function when all spots are equivalent.


Example: If Jim has 12 shirts, and needs to pack 7 for vacation, how many different combinations of shirts can he pack?

C(12, 7) = = 792 different combinations of shirts.