You and four friends are going to a movie. In how many different orders can you pick your friends up?
There are 4 friends - 4 choices for the first friend to be picked up.
For every choice of the first picked up, there are 3 friends left - 3 choices for the second friend to be picked up.
Following the pattern, 2 choices for the third friend, 1 choice for the fourth.
4*3*2*1 = 24