JS

(quick guide & examples)

The number of ways we can arrange a list of things.

The order in which it is arranged does matter.

A, B, C, AB, BC, etc... are not permutations of "ABC".

Permutation is "number of ways to arrange a list", not "number of variations".

The number of ways we can create from a list of things.

The order in which it is arranged does not matter.

* The order does not matter. So BA=AB, CA=AC, BC=CB, CAB = ACB = BAC, etc...