Permutations

Basic Counting Techniques

The Product Rule

This rule is applied when you make a sequence of independent choices. The total number of outcomes is found by multiplying the number of options at each step.

Definitions

A permutation is an ordered arrangement of a set of objects. For example, 3 distinct letters (A, B & C) can be arranged in 6 different permutations: ABC, ACB, BAC, BCA, CAB, CBA.