Factorial (!)
The product of all positive integers up to a number.
Definition
The factorial of a number n (written n!) is the product of all positive integers less than or equal to n.
Example
5! = 5×4×3×2×1 = 120
Calculation
Factorial=n!=n × (n−1) × … × 2 × 1
Example:5! =5 × 4 × 3 × 2 × 1
5! =120
5! =120