How to Use Numbers in Writing

1. How to Use Numbers in Writing Created by Hunter Brown Summer 2013

2. What is a Number? A number is a mathematical idea used to count, label, and measure. Numbers can be represented by numerals or words. Numerals or figures • 1/2 • √5 • 3 • π • 25 • XLI • 101 • 1,492 • MCM • 500,000 Words • One third • Five • Thirteen • Forty-six • Ninety-nine • One hundred • Twelve hundred • Eight thousand • Twenty thousand • Three million

3. General Rules In ordinary writing and MLA format • Spell out numbers which can be expressed as one or two words (one, thirty-six, ninety-nine, one hundred, fifteen hundred, two thousand, three million). • Use numerals for numbers with more than two words (2½, 101, 137, 1,275). In technical writing and APA format • Spell out numbers from one to nine (one, two, three, etc.). • Use numerals for 10 and above (10, 11, 12, etc.). In all contexts and formats • If you must begin a sentence with a number, spell the number out. NOT: 1994 was my birth year. BUT: Nineteen ninety-four was my birth year. OR: My birth year was 1994 (preferred). • There is often more than one acceptable way to write a number; once you choose a usage, stay consistent.

4. Commas in Numbers Use commas between groups of three digits in most figures of 1,000 or more. • 1,000 • 20,000 • 7,654,321 Following are some exceptions: • Page and lines numbers (page 1014) • Addresses (4132 Broadway) • Four-digit year numbers (1999) • Degrees of temperature (3071 °F) 1,000,000

5. Dates For dates, use cardinal numbers (1, 2, 3), not ordinal numbers (1st, 2nd, 3rd). NOT: My birthday is March 24th. BUT: My birthday is March 24. For three-part dates, you can use either of the forms below: • March 3, 1847 (month-day-year) • 3 March 1847 (day-month-year) If you use the month-day-year format in the middle of a sentence, place a comma after the day and the year. If you use the day-month-year format, no commas are necessary. • Alexander Graham Bell was born March 3, 1847, in Edinburgh, Scotland. • Alexander Graham Bell was born 3 March 1847 in Edinburgh, Scotland.

6. Dates Continued Centuries Spell out centuries in lowercase letters: • the twentieth century • the mid-nineteenth century Hyphenate centuries when they are used as adjectives before nouns: • eighteenth-century thought • first-century Christianity Decades • Decades are usually written out in lowercase letters (the twenties), unless they are part of special expressions (the Roaring Twenties). • Decades can also be expressed in numerals (the 1920s, the ‘20s). • Whichever form you use to express decades, be consistent. Year Designation The abbreviation BC follows the year, but AD precedes it. • 19 BC • AD 565 Some writers prefer to use BCE and CE, both of which follow the year.

7. Times When clock times precede a.m. or p.m., use numerals: NOT: ten-twenty a.m. BUT: 10:20 a.m. NOT: eight p.m. BUT: 8:00 p.m. Spell out hours expressed in quarter and half hours and hours followed by o’clock: NOT: 6:00 o’clock BUT: six o’clock NOT: a quarter to 12 BUT: a quarter to twelve NOT: half-past 10 BUT: half-past ten

8. Decimals Use numerals for numbers containing decimals: • 98.7 degrees • 5.5 million • 0.23 cm • 99.99% • $77.77 (Money amounts containing dollars and cents may be spelled out in rare situations, for example, in legal documents.) 3.14

9. Percentages • Use numerals to express percentages (75%, 9 percent). • Most style guides suggest that you • use the percent symbol (100%) in technical or scientific writing; • use the word percent (100 percent) in writing that requires numbers less frequently. • Once you choose a usage, stay consistent.

10. Units of Measurement Use numerals with units of measurement expressed as abbreviations or symbols. • 515 lbs • 0.45 cm • 20 Hz • 6’ 2” • 212 °F • 70 mph • ¥88,909 • $500 If the context is not technical, if the number is not a decimal and is below 9 (for APA) or can be spelled in two words or fewer (for MLA), and if the unit of measurement is spelled out, you may express the number in words: • The average U.S. resident eats almost four pounds of meat per day. • My brother is six feet two inches tall. • The temperature was a bone-numbing five degrees Fahrenheit. • The freight train crept along at eight miles per hour. • I bought this fine-looking truck for a mere five hundred dollars.

11. Roman Numerals Use Roman numerals • to differentiate popes, kings, emperors, queens, etc. with the same name (Henry I, Pope Benedict XVI); • to differentiate male members of the same family with identical names (Martin Luther King III); • to number the major sections of an outline or the acts in a play (Act I, Scene III); • to conform to an established terminology (Type II error); • to cite pages of a book that are numbered with Roman numerals (xxv-xxvi).

12. References American Psychological Association. Publication Manual of the American Psychological Association. 6th ed. Washington, DC: APA, 2010. Print. Hixon, Mamie Webb. Real Good Grammar, Too. 2nd ed. Dubuque, Iowa: Kendall/Hunt, 1997. Print. Modern Language Association. The MLA Handbook for Writers of Research Papers. 7th ed. New York: MLA, 2009. Print.