Numbers & Figures

Figures
Use figures for numbers 10 or greater; write out figures less than 10

Nearly 40 people attended the gathering. Only four people came to class.

Days of the month
Use figures for days of the month, omitting st, nd, rd, and th:

September 28 (not September 28th)
December 22 (not December 22nd)

Large figures
Use figures for sums that are cumbersome to spell out; however, spell out the words million and billion.

The campaign received a $25 million gift. (Not 25,000,000 million)
China has a population of roughly 1.9 billion.

Measurements

Use figures for measurements

6 feet
15 inches
9 cubic centimeters
33 percent (don't use 33% in a sentence, it is permissible in tables or charts)

Ages
Use figures for ages more than 10; spell out if less than 10.

The child is five years old.
For a 12-year-old student, she sure knows her history
The average student age at the college is 20.

Telephone numbers
Write phone numbers as follows:

Always list area codes and local exchanges on the Web since some visitors will be attempting to call from off campus, (e.g., x2000 or ext. 2000),.
Use dashes around area code, e.g., 704-894-2000)
Avoid using parenthesis around the area code, e.g., (704) 894-2000
Avoid using trendy listing methods, such as including periods, e.g., 704.894.2539
Also list toll-free numbers with a "1" for consistency (e.g., Call us at toll-free at 1-800-555-5555)

Time
Use figures for hours of the day:

5 p.m. or 5:30 p.m. (never 5:00 p.m., unless used in lists of events to preserve alignment of type).

Money
Use figures for amounts of money with the word cents or with the dollar sign (i.e., $5, $5.25, $.77 or 77 cents) unless tabulated in columns.

Numbers at the beginning of a sentence
Do not begin a sentence with numerals; supply a word or spell out the figures. Please note: numbers less than 100 should be hyphenated when they consist of two words:

Two thousand people attend the college. (If applicable, simply rewrite to use numerals: More that 2,000 people attend the college)
Eighty-eight percent of our students live on campus.
One-half of the class was late.