Combinatorics — introduction
A first taste of combinatorics without formulas: systematic listing of options, counting arrangements from a small set, counting combinations with a tree diagram, and counting pairs from n items.
Available exercises
Arrangements — systematic listing
From a small set (3 or 4 elements), count the number of 3-element arrangements without repetition.
Choosing pairs
Count how many different pairs you can make from n items.
Combinations — tree diagram
Count how many different combinations come from two small groups of options. A tree diagram is shown.