# What is 100 factorial ?

Steps to calculate factorial of 100

## How to calculate the factorial of 100

To find 100 factorial, or 100!, simply use the formula that multiplies the number 100 by all positive whole numbers less than it.

Let's look at how to calculate the Factorial of One hundred :

100! is exactly : 93326215443944152681699238856266700490715968264381621468592963895217599993229915608941463976156518286253697920827223758251185210916864000000000000000000000000

Factorial of 100 can be calculated as:
100! = 100 x 99 x 98 x 97 x ... x 3 x 2 x 1

The number of trailing zeros in 100! is 24

The number of digits in 100 factorial is 158.

## What Is Factorial?

A factorial is showed by an integer and an exclamation tag. In arithmetic, factorial is a multiplication process of natural numbers .

It multiplies the number by every natural number that is less than it .

Symbolically, it is showed as "!".

The function is used, among other things, to get the "n" way elements can be structured .

## Factorial Formula

To find the factorial of any given number, replace the exact value for n in the given formula :

n! = n × (n-1) × (n-2) × (n-3) × ….× 3 × 2 × 1

The expansion of the formula provides numbers to be multiplied together to receive the factorial of the number.

We can also calculate a factorial from the prior one. The factorial of any number is that number replicated the factorial of (that number minus 1).

So the rule is : n! = n × (n−1)!

Example :
100! Factorial = 100 x 99 x 98 x 97 x ... x 3 x 2 x 1 = 100 × 99! = 93326215443944152681699238856266700490715968264381621468592963895217599993229915608941463976156518286253697920827223758251185210916864000000000000000000000000

## What are Factorials Used For?

The best use of factorial is in Combinations and Permutations.

Example : Determine how to arrange letters without repeating?

There one way for 1 letter "a":
2 ways for two letters "ab": ab, ba.
There are 6 ways for 3 letters "abc": abc acb cab bac bca.
There are 24 ways for 1234 of the letters "abcd"

## Frequently Asked Questions on Factorial

### Can we have factorials for negative numbers ?

Negative integer factorials are undefined

### What Is 0!

Zero factorial or Factorial of 0 is simple, and its own value is equal to 1. So, 0! = 1.