Combination Solver
About Combination Calculator
The combination solver is an easy-to-use, free, and open source tool that calculates the total number of combinations, number of possible arrangements in a collection of items, and the number of solutions with particular values. Where n = total number of objects in the set, and r = number of choosing objects from the set. A combination is the number of selections of different items from distinguishable items when order of selection is ignored.