ABSTRACT
Generally, an exclamation mark (called an exclamation point in the USA) is used to express astonishment or surprise. In scientific and technical writing, you are unlikely to find many appropriate occasions to use one. But it is a legitimate signal, and can sometimes be used effectively to highlight a surprising fact or to reinforce a warning:
A special use of the exclamation mark is its use in mathematics to indicate a factorial (the product of all the positive integers from 1 to n), symbolised as n!. If you are using an exclamation mark in this special way in your text, avoid using the same mark to express astonishment or surprise, perhaps by using an expression such as ‘It is surprising that ...’ or ‘Surprisingly, ...’
