# Exclamation Mark Symbol

The exclamation mark symbol is used to represent the unary factorial operator. Typically the exclamation mark is used in an expression like this:

In plain language, this means take the factorial of the number five. Shown below are various formats of the exclamation symbol.

Symbol Format Data
! Unicode
33

TeX
!
SVG

### Usage

Factorial | Operator

The factorial operator is represented using the exclamation mark. The operator is unary, meaning that it only operates on one expression. The operator is useful when calculating combinations and permutations.

Permutations of Set | Formula

The number of permutations of n distinct items is given by n factorial. A permutation is a unique ordering or arangment of the set of items.

Permutation | Formula

The permutation formula describes the possible permutations of r elements out of a group of n elements where order does matter.

Combination | Formula

The combination formula describes the possible combinations of r elements out of a group of n elements where order does not matter.