Cardinal and Ordinal Numbers 

Cardinal and ordinal numbers up to ten are written out in non-technical text.

The ten players were suspended.
The tenth player was suspended.

Figures are used for cardinal and ordinal numbers greater than 10; for references to book elements (e.g., parts, chapters, footnotes, tables, and figures); and for all clock times, dates, percentages, decimals, and mathematical terms.

When numbers above and below 11 appear in the same paragraph, write all numbers under 10 as numerals for ease of comparison and appearance of consistency.

Numbers that begin a sentence are spelled out.

This question is explored in Chapter 6.
The break-and-enter occurred between 9 p.m. and 4 a.m.
There are 17 reasons for this.
In the 17th century things were different.
The rule applies to the first 6 months and the last 36 months.
The 1st and 12th items on the list.
In 1971, the sales tax rate was 5 percent in Ontario and 8 percent in Quebec.
The dispute centred on a two-foot discrepancy between the surveyor's plan and the fenced boundary.
Seventeen reasons exist for this.


Ordinals are spelled out as follows. Note that letters are lining; they are not superscripted.

1st, 2nd, 3rd, 4th, 5th, 6th, 7th, 8th, 9th, 10th, 11th, 12th ... 21st, 22nd, 23rd ...

Exception: Case reporter series use 2d and 3d.

Commas in Numbers 

In general, use commas between groups of three digits in most figures of 1,000 or more. However, no commas are used in the following numbers.

page 1029
regulation 5029
serial number 295728590
binary digit 011001001
temperature 2071 °C
acoustic frequency 2000 Hz

Inclusive Numbers 

Use of en dashes or hyphens in inclusive numbers (data, dates, etc.) follows the inclusive page number style of the work.

Inclusive Dates

Inclusive dates that refer to complete calendar years include all figures.


Inclusive dates that refer to fiscal and school years and other two-year periods omit the first two digits of the second number (or the first three digits where the first two are zeroes).

the 1989-90 academic year
the 2001-2 taxation year
the government’s budget for 2010-11

Inclusive Page Numbers

There are two styles of inclusive page numbers: general style and legal style. General style is used in works that follow APA or Chicago reference style. Legal style is used in works that follow McGill reference style.

For numbers below 100 (and where the first number is less than 100 and the second number is greater than 100), use all numbers. For numbers over 100, truncate to two digits in the second number unless the hundreds or thousands digit changes. For numbers between, e.g., 100 and 109, use only the final digit in the second number. Use hyphens (contra McGill).


General (APA/Chicago) Style

Include all numbers. Use en dashes.


Plural Numbers 

Plurals of numbers in a general sense may be written out.

Most workers plan to retire in their sixties.

In more specific usage (e.g., references to decades), an "s" follows the final digit (with no apostrophe).

The 1980s was the decade of greed.
The temperature was in the 20s.

Part and Chapter Numbers 

Part numbers (coded <PN>) are expressed in Roman numerals: I, II, III.

Chapter numbers (tagged <CN>) are expressed in Arabic numerals: 1, 2, 3.

Exception: Design preferences, whether inherited or invented, may prescribe that part or chapter numbers be spelled out (e.g., chapter numbers in casebooks typically are spelled out).

Note Numbers 

Note numbers follow all punctuation marks except an em dash, and are usually placed outside a closing parenthesis.

Two note numbers must not appear in immediate sequence (e.g., 13,14). If they do, combine them into one note.

Notes to tables or figures are not numbered in sequence with notes to text. They are generally set as superscript letters in alphabetical sequence or as note symbols in the sequence *, †, ‡, §, #. The order of the note placement follows the English reading pattern: left to right, top to bottom.

Adjectives and Possessives 

Distinguish between numbers with adjectives and possessive numbers with nouns.

Numbers with an adjective take no apostrophe; the number modifies the adjective that follows. Examples:

three months pregnant
four hours late
five feet tall

Possessive numbers with a noun take an apostrophe; the apostrophe can be replaced with "of." Examples:

six days' time
seven months' probation
eight years' experience


Generally, use symbols for currency units. Use words in casual or colloquial contexts. Amounts usually take singular verb.

The company earned $15 million (£7.86 million) last year.
I'd buy that for a dollar.
Last year, $15 million was spent on improvements.

Where it is necessary to distinguish or emphasize dollar amounts by national jurisdiction, use the following country abbreviations with the dollar symbol:

Canadian dollars: Cdn$100
US dollars: US$100
Australian dollars: A$100
New Zealand dollars: NZ$100

ISO 4217 currency codes, if used, should be used for all amounts. A space separates the currency code from the currency amount:

Canadian dollars: CAD 100
US dollars: USD 100
Australian dollars: AUD 100
New Zealand dollars: NZD 100