Combinations
When discussing permutations, we considered the situation where we chose [latex]r[/latex] items out of [latex]n[/latex] possibilities without replacement and where the order of selection was important. We now consider a similar situation in which the order of selection is not important.
combination
A combination is a selection of objects from a set without regard to the order in which they are selected.
Notation:The number of combinations of [latex]n[/latex] objects taken [latex]r[/latex] at a time is denoted by [latex]C(n, r)[/latex] and is given by:
Permutations and Combinations
You can view the transcript for “How to Use Permutations and Combinations” here (opens in new window).
You can view the transcript for “Permutation formula | Probability and combinatorics | Probability and Statistics | Khan Academy” here (opens in new window).
You can view the transcript for “Permutations and Combinations Tutorial” here (opens in new window).