# What is 1 factorial ?

Steps to calculate factorial of 1

## How to calculate the factorial of 1

To find 1 factorial, or 1!, simply use the formula that multiplies the number 1 by all positive whole numbers less than it.

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

1! is exactly : 1

Factorial of 1 can be calculated as:
1! = 1

The number of trailing zeros in 1! is 0

The number of digits in 1 factorial is 1.

## What Is Factorial?

A factorial is represented by an integer and an exclamation mark. In arithmetic, factorial is a multiplication treatment of natural numbers .

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

Symbolically, it is represented as "!".

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

## Factorial Formula

To find the factorial of any given number, change the exact value for n in the given method :

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

The expansion of the formula provides numbers to be multiplied at the same time to have 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 :
1! Factorial = 1 = 1 × 0! = 1

## 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 number factorials are undefined

### What Is 0!

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