# Permutations of a Set Formula

The number of permutations of a set is given by factorial, where is the number of elements in the set. A permutation is a unique ordering of the elements in a collection where order does matter. The formula returns the number of possible permutations.

Expression | Description |
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Number of elements in the set |

The number of permutations of a set is given by factorial, where is the number of elements in the set. For example, the number of permutations for the set is given by the formula below. Since there are elements in the set .