In the humanities, which generally follow Modern Language Association (MLA) style, use numerals only for specific numbers larger than one hundred: 353; 1,020. Spell out numbers one hundred and below and large round numbers: eleven, thirty-five, fifteen million. Treat related numbers in a passage consistently: The survey found that 9 of the 157 students had not taken a course on alcohol use.

The social sciences and other disciplines that follow American Psychological Association (APA) style use numerals for all but the numbers one through nine. Spell out numbers from one to nine even when they are used with related numerals in a passage: The survey found that nine of the 157 respondents had not taken a course on alcohol use. (An exception is the abstract of a paper, where numerals are used for all numbers. See 62a.)

If a sentence begins with a number, spell out the number or rewrite the sentence.

Rewriting the sentence may be less awkward if the number is long: In our program, 150 children need expensive dental treatment.