# Permutations

by
**alanmello**

Last updated 7 years ago

** Discipline: **

Math ** Subject: **

Algebra I
** Grade:**

11

Permuntations

Alan Mello P.4

Good to Know: Permutation is just like a combination with the only exeption order matters.Or in other words a permutation in an odered combination

Permutations basically have two types.

When repetition is not allowed

When repetition is allowed

Remember that the "!" symbol represents that the number is a factorial meaning that the number that "!" is assigned to is multplied by all the numbers that come before it.Example: 4! means 4x3x2x1

The permutation with repetition formula is as simple as

In permutations withought repetition you must reduce the amount of choices each time.in the case of having 16 possibilities you would multiply:16x15x14......x2x1= 20,922,789,888,000 posibilities

But if you would only like to chose 3 posibilites out of the 16 you would be able to arrange them like this16x15x14=3,360

Sources:http://www.mathsisfun.com/combinatorics/combinations-permutations.htmlhttp://mathforum.org/dr.math/faq/faq.comb.perm.htmlhttp://www.geeksforgeeks.org/write-a-c-program-to-print-all-permutations-of-a-given-string/

Permutations are used in so caled "combination locks" used for getting probabilites and also for creating and hacking computer software

Song

Permutations with repetition

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