1. 11-8 Factorials!!!!!!

2. Factorial: the product of the first n consecutive pos. integers
! factorial notation 5! 3! 7! 0!
= 5 ∙ 4 ∙ 3 ∙ 2 ∙ 1
= 120
= 3 ∙ 2 ∙ 1
= 6
= 7 ∙ 6 ∙ 5 ∙ 4 ∙ 3 ∙ 2 ∙ 1
= 5040
= 1

3. Example 1 Faster: count down until reach # in denom
You MUST know how to do this without a calculator!

4. Example 2 3 2
You need
Parenthesis on the bottom if there’s more than 1 factorial!!!!!

5. Example 3 n
n–1
n–2
n–3
n–4
n–5
n–6

6. Example 4
n+2
n+1 n
n–1
n–2
n–3
n–4
n–5
n–6

7. Example 5--Working backwards
Example 5--Working backwards! Write the expression as a ratio of factorials.

8. Example 6--Working backwards
Example 6--Working backwards! Write the expression as a ratio of factorials.