Permutations

P_n=n!

Result unit: — (number of arrangements)

What it describes

The number of different arrangements (orderings) of n elements.

P_n

number of permutations

n

number of elements

When arranging n elements, the first position can be filled in n ways, the second in

(n-1)

, and so on — hence the factorial. Order matters.

Arrangements in a row, ordering, anagrams (distinct elements).

In how many ways can 4 people be arranged in a row?

Substitution

n=4

Result

P_4=4!=24

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