NUMBERS 

Arabic versus Roman. Arabic numbers are 

generally easier to understand than Roman: 

3 or 4 rather than I11 or IV; 1988 rather than 

MCMLXXXVIII. 

Beginning of a sentence. Numbers at the beginning of a sentence are spelled out, but most sentences 

can be worded so as not to begin with a number. In 

the sentence "Four thousand eight hundred fifty tons 

was produced in 1986, and 5,180 tons in 1987," convenience requires that both quantities be expressed in 

figures. Rewrite as "The production was 4,850 tons in 

1986 and 5,180 tons in 1987." 

Compound modifier. Numbers less than 100 

preceding a unit modifier containing a figure are 

spelled out: 

twelve &inch guns 

two 314-inch boards 

120 &inch boards 

three 4-foot boulders 

Dates. In Survey reports dates are given as 

follows: June 20 (not June 20th), the 20th of June, 

the 2d or 3d (not 2nd or 3rd). In the Department of 

Defense the day and month are written "20 June," 

and in material quoted from that Department the 

style should not be changed. 

For consecutive years use the contracted forms: 

1934-35, 1890-91, 1986-87, 1900-10, 1907-8 (but, on 

a change of century, 1895-1902, and to avoid three 

ciphers together, 1900-1901). Fiscal years, water 

years, or meteorological years are written the same 

way: 1968-77. 

A.D. precedes the year; B.C. follows the year: A.D. 

937, 254 B.C.; A.D. 937 means anno Domini (in the 

year of our Lord) 937; 254 B.C. means the 254th year 

before Christ. 

Decimals. Decimals are expressed in figures. A 

zero should be supplied before a decimal point if there 

is no unit (both in text and in footnotes), and zeros 

should be omitted after a decimal point unless they 

indicate exact measurement: 0.25 percent, 90 percent 

silver. (See p. 119 for discussion of significant figures.) 

Doubled-up numbers. Avoid doubling up figures 

as shown in the following example: "The final survey 

made the total distance of levels run in 1976 38,307 

miles." Rewrite as "Including the final survey, the 

total distance of levels run in 1976 was 38,307 miles." 

Fractions. Fractions that stand alone are spelled 

out, but where the fraction is joined to a whole 

number figures are used: one-eighth, three-fourths, 

3l/z, 13/r (but l/2 page to 13/a pages). 

Write half a mile, a quarter of a mile (not a half 

mile or l/2 mile), but 2/s mile (1 kilometer). 

Figures are used for fractions in a unit modifier: 

Yz-inch pipe, %-point rise, 0.9-inch spacing. 

Indefinite expressions. Indefinite expressions are 

spelled out: the early seventies, in the eighties (but 

the 1980's). 

Large numbers. In large numbers, the word 

"million" or a similar group term is spelled out: 

20 million, 3 billion, $5 million (but use figures if 

other numbers in a series are given in figures: "The 

appropriation in 1952 was $780,000 and in 1953 was 

$2,000,000"). 

Ordinal numbers. Except in formal writing, in 

bibliographic citations of an edition of a work, and for 

day preceding month, figures are used for ordinal 

numbers beginning with 10th: 82d Congress, 20th 

century, 49th parallel, 141st meridian. 

When ordinal numbers appear in juxtaposition and 

one of them is 10th or more, figures are used for 

both: the 1st session of the 82d Congress, the 9th and 

10th Congresses. 

Quantities and measurements. Age, degree, 

measurement, money, percentage, proportion, time, 

and similar matters are expressed in figures: 6 years 

old, 27", 45 miles, 9 bushels, 24 pages, 16 by (or x) 

24 inches, $1.54, 17 percent, ratio of 1 to 4, scale of 

1:62,500, 10 o'clock, 10 p.m., 4:30 p.m. (but four centuries, three decades). 

Related numerical expressions. Figures are used 

in a group of two or more related numerical expressions, whether or not each number is less than 10: 

2 gold mines, 3 silver mines, and 8 copper mines; 

3 wells and 11 springs; tested at 4, 28, and 160 days. 

A unit of quantity or measurement, always expressed in figures (except in round numbers), does not 

affect the use of figures or other related or connected 

numerical expressions: "The five mines are 20 miles 

southwest of the town." 

Round numbers. Round numbers are spelled out: 

almost a thousand years, nearly a hundred feet, about 

a hundred wells (but 115 wells). 

Serial numbers. Figures are used for serial 

numbers: locality 259, Bulletin 725. 

Numbers 117 
Singular nouns. Avoid the common mistake of 

assigning plural verbs to numbers that have singular 

contexts, almost always in the passive voice: 

Eight hundred feet of sandstone and shale were [was] 

measured. (Not 800 individual feet but a single section of rock 

totaling 800 feet. Recast as, "They [we, I, she, he] measured 

800 feet of sandstone and shale.") 

Three million years were [was] required to excavate the gorge. 

(A single time lapse of 3 million years. Try recasting with "gorge" 

as the subject: "The gorge was excavated in 3 million years.") 

Four years were [was] spent in the field and 8 years were [was] 

spent in the office. (Problem can be avoided by recasting: Fieldwork took 4 years; office work took 8.) 

See also page 126. 

NOTEWORTHY NUMERICAL CONVERSIONS II 

[A la Johns Hopkins Magazine, as conceived by Solomon 

W. Golomb, University of California] I / 

One-half Soviet press agency = 1 demitasse 

Ten cards = 1 decacard 

Two thousand mockingbirds = 2 kilomockingbirds 

Two tribes = 1 diatribe 

One-trillionth dilly = 1 picodilly 

One billion antics = 1 gigantic 

One-millionth fish = 1 microfiche 

A~SO: J 

1021 picolos = 1 gigolo 

1012 microphones = 1 megaphone 

10 bicycles = 1 kilocycle 

10 millipedes = 1 centipede 

10 monologues = 5 dialogues 

1 milli-Helen = the face that launced 1 ship 

118 Numbers