10.1.3. Exclamation mark
An exclamation mark is used after an exclamatory word, phrase or sentence.
An exclamation mark is used after an exclamatory word, phrase or sentence such as ‘Look!’ or ‘How we laughed!’ Such exclamatory expressions are appropriate in texts that directly address the reader or audience, such as speeches or informal instructions, but are usually out of place in formal texts.
There should be no space between the exclamation mark and the preceding word, letter or number.
The imperative does not require an exclamation mark, but one may be used to add exclamatory force to a statement or a command.
In mathematical and statistical texts, the exclamation mark identifies a factorial. Here too, there should be no space between the exclamation mark and the preceding number:
6! = 6 × 5 × 4 × 3 × 2 × 1