representing some departures from Chicago style (which covers numbers in Chapter 9):
- spell out zero through nine
- use numerals for 10 and higher
- use numerals with thousands, ten thousands, and hundred thousands (4,000; 50,019; 100,000; 807,996)
- with round numbers greater than one million (million, billion, trillion), write out the words for one million (or billion, etc.) through nine million; use the numeral and word for numbers that begin with 10 and higher (10 million, 64 billion, 835 trillion)
- for large, round fractions using decimal points, use a numeral and spell out million, etc. (2.3 million, 4.5 billion, 8.7 trillion)
- the same rules apply to ordinals (second, 21st, 127th) that apply to cardinals (two, 21, 127); do not superscript ordinals
- page numbers are always numerals, including 1 through 9, no matter where they appear
- in course catalogs, use numerals for credits (1 credit, 24 credits, a 2-credit course)
- spell out a number at the beginning of a sentence (Twenty-five students are enrolled. Three credits of history must be completed by the senior year.)
- do not hyphenate number as part of a compound adjective (number one city, number two ranked team) or as a predicate adjective (We are number one in the league.)