The symbol present on some calculators, typically denoted as “!”, represents a mathematical operation. This operation, known as the factorial, calculates the product of all positive integers less than or equal to a given non-negative integer. For example, 5! (read as “5 factorial”) equals 5 4 3 2 1, which results in 120.
The factorial function is fundamental in various areas of mathematics, including combinatorics, probability, and calculus. Its ability to compute the number of ways to arrange or select items from a set makes it invaluable in solving problems related to permutations and combinations. Historically, its notation and use have evolved to simplify complex calculations and provide a concise representation of repeated multiplication.