Handbook of style in use at the Riverside Press/The Use of Figures
THE USE OF FIGURES
Spell out, in ordinary reading matter, all round numbers and numbers of less than three digits, unless of a statistical or technical character, and unless occurring in groups of six or more, following one another in close succession. Treat all numbers in connected groups alike: if the largest contains three or more digits, use figures for all.
Spell out words to express ages; as, The school ages are from five to eighteen.
Spell out numbers of centuries, of sessions of Congress, of political divisions, of streets, avenues, etc., and references to particular decades, unless the saving of space is essential; as, eighteenth century; seventeenth-century writers; Second Dynasty; Sixty-first Congress, First Session; Second Congressional District; Eighth Ward; Fifty-ninth Street and Ninth Avenue; in the early eighties.
Spell out numbers of army corps, divisions, brigades; use figures for regiments; as, Sixth Corps, First Division, Second Brigade, 41st Massachusetts, 2d Cavalry, 1st Battalion. But where only an isolated reference is made to one or more regiments, and the corps or divisions are not mentioned, the spelled-out form is proper; as, The Seventh New York Regiment; the Twentieth Ohio.
Sums of money, occurring in isolated cases in ordinary reading matter, should be spelled out; as, The admission was two dollars. Where several such numbers occur close together, and in all matter of a statistical character, use figures; as, Admission: Men, $2; women, $1; children, 25 cents.
The time of day is best spelled out when it occurs in ordinary reading matter; as, at four; at half-past two in the afternoon; at seven o’clock. In statistical matter, in enumeration, and always in connection with am. and p.m., use figures; as, at 4.15 P.M. (omit “o’clock” in such cases).
All numbers that begin a sentence in ordinary reading matter should be spelled out; if this is impracticable, the sentence itself should be reconstructed.
Figures should be used with per cent, in matter of a statistical character, but not in other cases. Do not use the % sign in any case.
Figures are used to express degrees of heat; as, 71° F.; or specifications of gravity; as, The specific gravity of lead is 11.352.
Records of votes, and of time in a race, are expressed more clearly in figures; as, 20 yeas to 41 nays; one mile in 2 minutes, 23½ seconds.
Numbers containing decimals or fractions are usually put in figures; but do not use a fraction alone, except a decimal. For example, 145.1 cm.; .1 cm.; 2½ yards; but not ½ mile.
In dates omit d, th, and st after figures; as, October 2, 1902; November 1, December 4. Use the forms 2d of November, 1st of March, 4th of June, etc., when the day precedes the month,
Where numbers are spelled out, express the amount by hundreds rather than by thousands; i.e., twenty-eight hundred and sixty, rather than two thousand eight hundred and sixty.
In printing connected consecutive numbers, omit the hundreds from the second number, and use an en dash between the figures; as, 1910–11; 230–33. But, of course, 299–301. Note that in indexes and footnotes, the citations of immediately consecutive pages are sometimes to be printed thus: 33, 34, 35; 33, 34; and sometimes thus: 33–35; 33–34; the distinction being that, where the figures are connected by the dash, the subject is treated continuously on the pages referred to, whereas the disconnected figures show that the subject is mentioned on each page cited, but not to the exclusion of other subjects. The copy must be followed strictly in such cases.
Use commas with five or more than five figures; as, 10,579,153,700; but 2634. This rule does not apply to tabular work, where in any column there are more than four figures. In such cases, the use of the comma with the larger number requires its use throughout the column.
Numbered paragraphs or sub-sections should begin: (1)(2)or 1. 2. The proper space after these is an en quad after the period, and a 3-em space after the parenthesis.