Overview
Combinatorics is a mathematical subject which counts of the number of groups within a given set of items. It is used extensively in probability and statistics. When each combination (or permutation) can be assumed to be equally likely, the calculation of probabilities reduces down to just counting the number of combinations (or permutations).
Topics
- Permutations - collections where the order of items in the collection matters
- Combinations - collections where the order of items does not distinguish between collections.