Factorial notation is the product of all positive integers from 1 up to the given number.
The factorial of a number n is denoted by placing an exclamation mark (!) after the number. For example, 4! represents the factorial of 4.
To calculate the factorial of a number, simply multiply all the positive integers from 1 up to the given number. For example, 5! = 5 x 4 x 3 x 2 x 1.
Factorial notation is used in permutations and combinations, where it represents the number of ways to arrange or choose a certain number of elements from a set.
Calculate the following factorials:
Khan Academy's "Factorials and Combinations" video tutorial
"Introduction to Probability" by Blitzstein and Hwang, Chapter 3 on permutations and combinations