Permutation

Permutation

## Definition / Concept

A permutation is an arrangement of objects in which the order of arrangement matters.

The number of ways of arranging $$r$$ objects selected from $$n$$ distinct objects is denoted by:

$$^nP_r$$

## Formula

$$^nP_r=\frac{n!}{(n-r)!}$$

## Usage

- Used whenever selection and arrangement are both involved and order matters.