Combinatorics
7 tools
Choose and arrange
Combinations and arrangements, with or without repeats.Stars and bars
Share things among boxes, with a minimum per box.Special numbers
Catalan numbers, derangements and Stirling numbers.Pascal explorer
Pascal’s triangle, coloured by remainder mod .Probability simulator
Run an experiment many times for an estimate with a margin.Grid maker
Draw and colour grids of any size.Network board
Draw a graph; check connected, bipartite, Euler path.