Conventions of Composition Rule 123
Rule: Represent numbers in words, not figures, as a general rule, in formal writing. You may use figures for dates (as in April 4, 2002 [omit st, nd, rd, th]); any number requiring more than two words (as in 123); numbers in a set of statistics; page, line, chapter, act, or scene, etc.; or street-numbers. If a number is the first word in a sentence, you must write it out, even if it meets one of the above criteria for writing it as a number.
Note: Multi-word numbers from twenty-one to ninety-nine are hyphenated if used as adjectives. Higher numbers: one hundred and twenty-one, etc.
Examples:
Correct: Nineteen hundred fifty four marked a watershed year for the United States.
Correct: In 1954, our Supreme Court decided one of its most important cases ever.
Correct: I had twenty-seven dresses, but not a thing to wear to the wedding.
Practice deciding which numbers to spell out:
- I bought 10 pies, 6 doughnuts, and 200 gummy worms during the time I lived at 11 Interlaken Road.
- Jackie's 137 home runs and Michael's 2186 dunks make them stand out forever as greats.
- Between 10 and 15 kids each year go on semester programs.
- 100 percent of the kids on that team plan to play in the WNBA.
Resources for further explanation of when to spell out numbers:
Grammarly's When Should I Spell Out Numbers?
Purdue OWL's Writing Numbers