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Factorial

Definition Of Factorial

Factorial denoted as n!, with n > 0, is an expression, which is the product of all positive 
integers starting with n and counting backward to 1.
For example, 4! = 4 . 3 . 2 . 1 and 
n! = n . n-1 . n-2 . . . . 3. 2. 1

More About Factorial

By definition, factorial of zero is 1. That is, 0! = 1

Video Examples:Factorials - Evaluating Factorials! Basic Info
 

Solved Example on Factorial

Ques: Find the factorial of 8.

Choices:

A. 40,320
B. 40,230
C. 41,320
D. 41,230
Correct Answer: A

Solution:

Step 1: Factorial of 8 is 8 × 7 × 6 × 5 × 4 × 3 × 2 × 1 = 40,320.