3! = 3 × 2 × 1 = 6. Factorial of n is the product of all positive integers from 1 to n. Factorials appear in permutations combinations proba...
3! = 3 × 2 × 1 = 6. Factorial of n is the product of all positive integers from 1 to n. Factorials appear in permutations combinations probability and the binomial theorem. Key values to memorize are: 0!=1 1!=1 2!=2 3!=6 4!=24 5!=120 6!=720 for competitive exam speed and accuracy.