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How Do You Put Factorial in Calculator

Reviewed by Calculator Editorial Team

Factorials are a fundamental concept in mathematics, often used in combinatorics, probability, and algebra. This guide explains how to calculate factorials using different calculators and provides a built-in factorial calculator for quick calculations.

How to Calculate Factorials

The factorial of a non-negative integer n, denoted by n!, is the product of all positive integers less than or equal to n. For example, 5! = 5 × 4 × 3 × 2 × 1 = 120.

Step-by-Step Guide

  1. Identify the number for which you want to calculate the factorial.
  2. Multiply the number by each positive integer less than it until you reach 1.
  3. For example, to calculate 4!:
    • 4 × 3 = 12
    • 12 × 2 = 24
    • 24 × 1 = 24
  4. The result is the factorial of the original number.

Note: Factorials are only defined for non-negative integers. Attempting to calculate the factorial of a negative number or a non-integer will result in an error.

Different Calculator Methods

There are several ways to calculate factorials using calculators:

Scientific Calculator

Most scientific calculators have a dedicated factorial button (often marked with an exclamation mark). Simply enter the number and press the factorial button to get the result.

Programmable Calculator

If you have a programmable calculator, you can write a simple program to calculate factorials. The program would involve initializing a variable, using a loop to multiply the variable by each integer from 1 to n, and then displaying the result.

Online Calculator

Many online calculators provide a factorial function. You can enter the number and click the calculate button to get the result. The calculator on this page is an example of an online factorial calculator.

Spreadsheet Software

Spreadsheet software like Microsoft Excel or Google Sheets has a built-in factorial function. You can use the FACT function to calculate factorials directly in a cell.

Factorial Formula

The factorial of a non-negative integer n can be calculated using the following formula:

n! = n × (n-1) × (n-2) × ... × 1

For example, 6! = 6 × 5 × 4 × 3 × 2 × 1 = 720.

Note: By definition, 0! = 1. This is because there is exactly one way to arrange zero items.

Worked Examples

Let's look at a few examples to illustrate how to calculate factorials.

Example 1: Calculating 3!

3! = 3 × 2 × 1 = 6

Example 2: Calculating 7!

7! = 7 × 6 × 5 × 4 × 3 × 2 × 1 = 5040

Example 3: Calculating 0!

0! = 1 (by definition)

FAQ

What is the factorial of 0?
The factorial of 0 is defined as 1. This is because there is exactly one way to arrange zero items.
Can I calculate the factorial of a negative number?
No, factorials are only defined for non-negative integers. Attempting to calculate the factorial of a negative number will result in an error.
What is the difference between factorial and permutation?
Factorial is the product of all positive integers up to a given number. Permutation is the number of ways to arrange a subset of items from a larger set. The permutation formula involves factorials.
How do I calculate factorials in Excel?
In Excel, you can use the FACT function to calculate factorials. For example, to calculate 5!, you would enter =FACT(5) in a cell.
What are some real-world applications of factorials?
Factorials are used in combinatorics to calculate permutations and combinations. They are also used in probability, algebra, and physics.