Ximpledu

Factorial

See how to solve a factorial n!
(+word examples).
4 examples and their solutions.

Factorial

Formula

n! = n⋅(n - 1)⋅(n - 2)⋅ ... ⋅3⋅2⋅1
Multiply from n to 1.
Meaning: Pick & arrange n things
1! = 1
0! = 1
0! is defined as 1.

Example

5!
Solution

Example

7!4!
Solution

Example

4 letters: a, b, c, d
Find the number of ways to arrange the letters.
Solution

Example

3 letters: a, b, c
4 numbers: 1, 2, 3, 4
Find the number of ways to arrange the letters and the numbers
when all letters are adjacent to each other.
Solution