Factorial Basics
What is the definition of n! for a positive integer n?
n!=n×(n−1)×⋯×1
5! / 5!
1
11! / 10!2!
11 / 2!
15! / 11!3!2!
15 x 14 x 13 x 12 / 3!2!
Write out the expanded form of 5!
5x4x3x2x1
7! / 6!
7
8! / 6!3!
8 x 7 / 3!
13! / 8!4!2!
13 x 12 x 11 x 10 x 9 / 4!2!
Write out the expanded form of 6!
6×5×4×3×2×1
9! / 7!
9 x 8
7!5! / 2!
7 x 6 x 2!
9!4! / 6!5!
9 x 8 x 7 / 5
Compute 4!
24
12! / 10!
12 x 11
10!3! / 8!
10 x 9 x 3!
7!5! / 5!3!
7 x 6 x 5 x 4
Compute 8!
40320
15! / 13!
15 x 14
10! / 5!3!
10 x 9 x 8 x 7 x 6 / 3!
8!4! / 5!2!
8 x 7 x 6 / 4 x 3