We'd like to use analytics cookies to understand which symbols people look up, so we know what to research next. They are not used for advertising and we set none of them unless you say yes. What we store.
An exclamation mark after a number, multiplying it down to one.
Also known as: Factorial, Exclamation operator, N factorial
An exclamation mark after a whole number means multiply it by every whole number below it down to one. Zero factorial is defined as one, which is a convention chosen to make counting formulas work rather than a result that can be derived from the definition.
Denotes the product of every positive integer up to and including the number written before it.
Contexts: Mathematics
Is defined to give one at zero, a convention adopted so that formulas for arrangements and combinations hold without special cases.
Contexts: Mathematics
Is written after its argument rather than before it, which makes it one of the few postfix operators in ordinary mathematics.
Contexts: Mathematics
An upright stroke tapering downwards with a separate dot beneath it, set immediately after a numeral.