Factorial of a Number

Factorial of a Number

Factorial of a number n can be defined as product of all positive numbers less than or equal to n. For example, the factorial of 6 is 1 × 2 × 3 × 4 × 5 × 6 = 720

Examples

The following table provides few examples of factorial of a number.

NumberFactorialResult
1! 1 1
2! 1 × 2 2
3! 1 × 2 × 3 6
4! 1 × 2 × 3 × 4 24

Note: In Mathematics, factorial of a number is represented by exclamation mark.

Calculator

The following calculator will help you to find the factorial of any given number.

Why does 0! = 1?

We Know That

NumberFactorialResult
4! 1 × 2 × 3 × 4 24
3! 1 × 2 × 3 6
2! 1 × 2 2
1! 1 1

Now turn this around

NumberCalculationResult
4!5! / 524
3!4! / 46
2!3! / 32
1!2! / 21
0!1! / 11

In this way a reasonable value for 0! can be found.

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