Calculate combinations nCr: the number of ways to choose r items from n when order does not matter.
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Choosing 3 people from a group of 10 gives 10C3 = 120 possible groups.
Calculate combinations nCr: the number of ways to choose r items from n when order does not matter. The result is intended for quick estimates, checking arithmetic and comparing scenarios. When a result affects a contract, tax filing, medical decision, building-code requirement or other high-stakes situation, verify the result with the appropriate professional or authoritative source.
From 10 distinct items, selecting any 3 without caring about order gives 120 combinations: 10! ÷ (3! × 7!).
Picking ABC is the same selection as CBA when order does not matter.
The standard formula assumes no repeated selection and distinct available items; use permutations if position matters.
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Calculate combinations nCr: the number of ways to choose r items from n when order does not matter.
nCr = n! ÷ (r!(n−r)!).
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