 # Permutations and Combinations for Probability

Videos and lessons to help High School students learn how to use permutations and combinations to compute probabilities of compound events and solve problems.

• Define n! as the product: n! (n  1)!   3! 2! 1.
• Understand that a permutation is a rearrangement of the elements of an ordered list and calculate probabilities using the permutation formula P(n,r) = n!  (n  1)!     (n  (r  1)) = n!/(n  r).
• Understand that a combination is the number of ways to choose r items from a set of n elements and calculate probabilities using the combination formula C(n,r) = P(n,r)/r! = n!/[(n  r)! r!].

Common Core: HSS-CP.B.9

Factorials and Permutations.

Permutations and Factorials
This video explains how to write permutations in terms of factorials.

Permutations and Combinations - word problems.

Probability -- Combinations and Permutations
Definition of the fundamental counting principle and permutations, solving for permutation, solving for permutations with repetition, definition of combinations, solving for the number of different combination, solving for the number of different combinations of multiple events.

Probability with Combinations and Permutations.

Probability Involving Permutations and Combinations.

Try the free Mathway calculator and problem solver below to practice various math topics. Try the given examples, or type in your own problem and check your answer with the step-by-step explanations.  