4.9 Exclamation mark
The exclamation mark—also called an exclamation point in the US—follows emphatic statements, commands, and interjections expressing emotion. In mathematics, an exclamation mark is the factorial sign: 4! = 4 × 3 × 2 × 1 = 24; 4! is pronounced ‘four factorial’. In computing it is a delimiter symbol, sometimes called a ‘bang’. See
Avoid overusing the exclamation mark for emphasis. Although often employed humorously or to convey character or manner in fiction, in serious texts it should be used only minimally.
As with a question mark, an exclamation mark at the end of a sentence functions like a full point, and double punctuation should not be used. For a full account of the use of punctuation with quotation marks see