Math Calculators
Probability calculator.
Compute basic probability, combinations C(n,r), and permutations P(n,r). Choose a mode and the result updates as you type.
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Understanding probability
Probability quantifies how likely an event is to occur, expressed as a number between 0 and 1 (0% to 100%). The basic probability formula is P = favourable outcomes / total outcomes. Combinations C(n,r) = n! / (r!(n-r)!) count selections where order does not matter. Permutations P(n,r) = n! / (n-r)! count arrangements where order matters.