A television show had 22 shows during their first season, 23 shows during their second season, and 20 shows during their third season. If Sarah wanted to watch all three seasons, how many different combinations are there that she could watch all of the shows?
clearly, there are 22*23*20 = 10,120 different ways to pick one of each show, one from each season.
On the other hand, if she just wanted to pick all possible subsets of the collection of the 65 episodes available, then there are 2^65 - 1 sets of episodes she could watch.