Methods of counting (including permutations and combinations) form part of discrete mathematics. This branch of mathematics is important to any student intending to take a full part in a society based on technology and communication. Calculations of probabilities often make use of the ideas in this topic. The binomial theorem is a powerful algebraic application of combinations which in turn leads to the binomial probability distribution.

notes - counting methods, ...
multiplication principle, addition principle, factorials, "together" arrangements, arrangements involving identical objects, circular arrangements, permutations, combinations, inclusions/exclusions, choosing objects from a set with distinct subsets, Pascal's triangle, binomial theorem

problems sheet - counting methods, ...

activity page - sequences - Pascal's triangle

resource page - Pascal's triangle

Counting techniques activities - Discrete Mathematics Project

problems - Math Forum

Pascal's triangle and the ice cream cones - Math Forum

factorials from 0! to 999!

Amazing Mathematical Object Factory
Generate permutations, combinations, partitions, subsets, ...

Combinatorial Object Server
Generate permutations, combinations, partitions, subsets, ...

random permutations
Generate random permutations of integers. Enter the number of permutations and the number of integers.

bar codes

• How do bar codes work?
• Make your own bar codes.