Spell out numbers from one through nine; use numerals from 10 and up, including ordinal numbers (ninth, 22nd).
Exceptions: Always spell out numbers at the beginning of a sentence. When listing children's ages, use numerals throughout.
Their children are Joy, 13, Bill, 6, and Myron, 2 1/2.
When it's not a list, use a 5-year-old, the terrible twos, she's in her 20s, and Jack's 20-year-old son.
For large round numbers, use words as 10 million. For currency, use the dollar sign: $10 million but not the cents sign; write out the word: 52 cents.
Avoid putting numbers next to numbers in a sentence - separate the numbers with words if possible.
Telephone numbers: The standard formatting for phone numbers in university publications is 906-227-1234 and 800-227-1111.
Fractions: For fractions, write out the words: one-fourth, one-half in body copy; the fraction key is difficult to read and increases the potential for error. Use the fraction key for children's ages, charts and tables.