Fact of the Day: 03/01/2023

In everyday language, we often use exclamation marks for emphasis. For example, you might say that a house is “really big!” to drive home how big it is. Did you know that the exclamation mark is also used in mathematics? Its purpose is not emphasis, though. 

Factorials are a shorthand way of writing a special kind of multiplication, and they use exclamation marks. For example, “4!” is “four factorial.” The factorial function isn’t too different from a power. Really the only difference is that you’re not multiplying the number by itself a specified number of times; you’re multiplying it by every whole number less than it all the way down to 1 (sec. 1). For example…

• 1! = 1
• 4! = 4 x 3 x 2 x 1
• 8! = 8 x 7 x 6 x 5 x 4 x 3 x 2 x 1

You may be wondering, when would you ever need to use factorials? They’re used a lot in calculations involving combinations and permutations, and you may even see them mentioned in a probability class (sec. 4). Regardless of where you find them, though, now you know what they mean.

Reference(s): https://www.mathsisfun.com/numbers/factorial.html 

Fact Author: Ace

Fact Editor: Ace

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