Calculadora de Fatorial — Formula

Factorial, Permutations, and Combinations

Factorial

n! = n × (n-1) × (n-2) × ... × 2 × 1

0! = 1 by convention.

Permutations (order matters)

P(n, r) = n! / (n-r)!

Number of ways to arrange r items from n distinct items.

Combinations (order doesn't matter)

C(n, r) = n! / (r! × (n-r)!)

Number of ways to choose r items from n without regard to order.