3.4 Numbers and Dates
This section covers numbers, dates, and form of inclusive numbers. All guidelines and examples follow the Chicago Manual (8.1-80). As numbers and dates appear frequently in collection frameworks, especially in the Scope and Content Note, the guidelines are intended to clarify NDLP style practices.
Guidelines for spelling out numbers:
Numbers in series: When enumerating a series, use numerals:
Numbers in the same sentence but not part of the quantified category may be treated differently:
Consistency: When small and large numbers occur together in a group, set them all in numerals for consistency. When listing sets of numbers, Chicago 8.8 advises that "if you must use numerals for one of the numbers in a given category, then for consistency's sake use numerals for them all."
Quantities (Chicago 8.3-31):
Fractions (Chicago 8.14) are hyphenated as either adjectives or nouns (e.g., a two-thirds majority, two-thirds of those present). For decimal fractions (Chicago 8.17), use numerals (e.g., 3.14, 0.02).
Use numerals for numbered items such as parts of a book (Chicago 8.32) (e.g., chapter 5, part 2, page 35, volume 4).
Guidelines for spelling out numbers: (Chicago 8.33-46)
The year alone (Chicago 8.34) should be expressed in numerals, unless it is at the beginning of a sentence (Chicago 8.9). Era designations (Chicago 8.41) should be given in capitals, with the following style for periods and spacing: A.D. 1800, 75 B.C.
The day of the month (Chicago 8.36) in running text, notes, and bibliographies is written in the sequence month-day-year, with the year set off by commas:
Write the day of the month as a cardinal number (e.g., April 18, not April 18th).
Month and year (Chicago 8.39) are written in the sequence month-year with no internal punctuation (e.g., April 1993).
Centuries and decades (Chicago 8.40) should be spelled out in lowercase letters (e.g. ninth century, twentieth century). Spell out decades (the sixties, the seventies) or if the decade is identified by the century, write them as plural numerals (1920s, 1880s).
Compound adjectives should be hyphenated (e.g., a twentieth-century school of thought).
Time of day (Chicago 8.47) normally should be spelled out in text (e.g., quarter of four, noon, seven o'clock), but for emphasis write time in numerals, capitalizing A.M. and P.M. (2:30 P.M., 7:30 A.M.)
Form of Inclusive Numbers
Guidelines for form of inclusive numbers (Chicago 8.68-73):Inclusive numbers: Follow this model, which appears in Chicago 8.69:
Separating numbers with dashes (Chicago 8.68): Always write "167-72," never "from 167-72." As the dash implies 'from' and 'to,' it is redundant to use the words as well as the dash. Without the dash, however, write "from 167 to 172."
Inclusive years (Chicago 8.71):
When referring to years within the same century but after the first year of that century, use this style:
When inclusive years occur in titles, express all the digits:
The Coolidge Era and the Consumer Economy, 1921-1929.If, however, the title of a published work contains abbreviated inclusive dates, the abbreviation should be retained.
When displaying the span of an individual's life, express all the digits: