Ms. Hamilton's eighth-grade class wants to participate in the annual three-person-team basketball tournament.  Lance, Sally, Joy, and Fred are chosen for the team.  In how many ways can the three starters be chosen?
I need to count the number of ways to choose three people out of four, without regard to the order of the selection. This is a combination problem, not a permutation problem, because the order does not matter. I can use the formula for combinations, which is nCr = n! / (r! (n - r)!), where n is the total number of people and r is the number of people chosen. In this case, n = 4 and r = 3, so I plug those values into the formula and simplify. nCr = 4! / (3! (4 - 3)!) = 4! / (3! 1!) = (4 * 3 * 2 * 1) / (3 * 2 * 1 * 1) = 4. There are 4 ways to choose the three starters for the team. 