Words or Numerals

Generally, use words in reference to numbers one through nine, and numerals in reference to numbers 10 and above.

  • All four sessions were attended by at least 15 people.
  • Three finalists were chosen from the pool of 52 candidates.

Numerals are always used to refer to time of day, dates, ages, percentages—with “percent” always spelled out, not indicated by the percent sign:

  • Classes for children 6 and older begin at 8 am on May 10.
  • Tuition is not expected to increase more than 3 percent.

If the specific age is used as an adjective or as a substitute for a noun, it should be hyphenated. Don’t use apostrophes when describing an age range.

  • A 21-year-old student.
  • The student is 21 years old.
  • The girl, 8, has a brother, 11.
  • The contest is for 18-year-olds.
  • He is in his 20s.

Ordinal numbers

Generally, the same guideline applies as in words and numerals. Use words to refer to ordinal numbers first through ninth, and numeral versions of ordinal numbers 10th and above.

  • He graduated first in his class, while his twin brother graduated 20th.
  • All of the children in fifth grade were mentored by students in 10th grade.

Note: Word processing programs like MSWord often superscript ‘th’ and ‘st’ in a smaller font size automatically, but in both print and online, we plan to use the same font size and weight.

More and Over

Over and under indicate place. Greater than and less than indicate degree. Use more than or fewer than to reference a numeric value.

  • Fewer than 4 percent of new hires decline healthcare benefits.
  • More than 5,000 graduates became donors within five years of graduation.
  • Less than half of all freshmen live off campus.

Telephone numbers

Use figures: 865-555-1500. Use hyphens, not periods.

For toll-free numbers: 800-111-1000.

If extension numbers are needed, use a comma to separate the main number from the extension: 865-555-1500, ext. 2.


Always use figures in numbered addresses. Abbreviate Ave., Blvd., and St. and directional cues when used with a numbered address. Always spell out other words such as alley, drive and road. If the street name or directional cue is used without a numbered address, it should be capitalized and spelled out.

If a street name is a number, spell out First through Ninth and use figures for 10th and higher.

Examples of correctly formatted addresses:

  • 101 N. Grant St.
  • Northwestern Avenue
  • South Ninth Street
  • 102 S. 10th St.
  • 605 Woodside Drive


No apostrophe: 1920s, 1980s, mid-1970s
Spell out thirties, forties, fifties, sixties