Permutation Formula

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

Example

If we have four animals the possible combinations of four choose three is:

The set of four animals:

{🦕,🐓,🦎,🐟}

There are twenty-four possible permuations of four choose three:

Note that the order does matter. The permutation [🦕,🐓,🦎] is different form [🐓,🦕,🦎], because although they contain the same elements, they have different ordering.

Example

This example shows the possible permutations of four choose two using the permutation formula.

The set of four animals:

{🐢,🐥,🐖,🐋}

There are twelve possible permuations of four choose two: