1. 9-4 Permutations (pg 381-383) Indicator – D7

2. Permutation: an arrangement, or listing, of objects in which order is important (you can use the to find the # of possible arrangements) Ex: How many ways can 5 classes be arranged during 1 st to 3 rd period? 5 P 3 = FCP 5X4X3= 60

3. If the permutation includes all the members it can be written as a factorial – n! (n members = n x (n-1) x (n-2)… × 1 or n!) (Start at n and count backward until you get to 1, multiply all of those numbers.) Example: How many ways can you arrange12 students in a class picture? 12P12 = 12 × 11 × 10 × … × 1 or 12! = 479,001,600 ways!! Calculator Keys: 12 PRB > > ! = Screen Looks like: 12! Press = again.

4. You Try There are 8 runners in a 5K race. How many different arrangements are there for the 1 st, 2 nd, and 3 rd places 8 P 3 Answer: 8 × 7 × 6 = 336 different arrangements of winners

5. There are 5 students in line to board a bus. How many different ways could the students board the bus? 5 P 5 Answer: 5! = 120 different arrangements