Think about the documents you produce: newsletters, bulletins, reports, letters, programs—and more. Looking over publications at an associational meeting, I was struck by how many numbers are used in our printed materials. Expressing numbers in print can be tricky.

Even the reliable Gregg Reference Manual concedes, “The rules for expressing numbers would be quite simple if writers would all agree to express numbers entirely in figures or entirely in words.”

Gregg identifies two distinct usage styles. The figure style uses figures for most numbers above 10, while the word style uses figures only for numbers above 100. Since there are exceptions to both styles, be ready to use each style as the situation demands. You may want to formulate a style sheet for your documents.

Some appropriate guidelines based on the most-used figure style:

• Spell out numbers from 1 through 10; use figures for numbers above

Exception: When numbers need to stand out for quick comprehension—as in the statement of this rule—use figures.

Exception: Some authorities suggest spelling out only single-digit numbers—1 through 9—and using figures starting with 10.

Exception: Use numbers when referring to numbers as numbers (such as, think of a number between 6 and 10).

Exception: Use numbers with U.S. highway designations (State Route 5; I-95), with emphatic references to age (the class for 3-year-olds), with periods of time (a 3-month study), specific measurements (a 4- by 6-foot rug), and page numbers (page 7).

• Spell out a number above 10 when you intend it to be indefinite:

I have a million things to do today; he has a hundred excuses.

• Spell out numbers at the beginning of a sentence:

Forty-five assistants attended the session.

• Spell out fractions:

Remarkably, one-third of the attendees were from our state.

• Spell out most ordinals:

It was the organization’s thirtieth anniversary.

• Spell out references to ages that are not given as statistics:

My daughter just turned thirteen.

• Spell out periods of time:

The pastor called fifteen minutes ago.

• Spell out measurements that lack technical significance:

The box weighed at least ten pounds.

• Use the same style to express related numbers. If any are above 10, put them all in

There are 24 pens in the package, but only 3 are red. The old package had 12 black, 6 blue, 6 red.

But: Our six volunteers prepared 104 box lunches, 9 pies, and about 1000 cookies—all in one morning. Figures are used for all the related items of food; six and one are spelled out since they are not related and are not over 10.

• When numbers run to five or more figures, use commas to separate thousands, etc. The comma may be omitted in four-digit whole numbers except in columns with larger numbers requiring

These guidelines are meant to cover our most commonly used situations. You will find extensive rules in

The Gregg Reference Manual; Tenth Edition.