A subscriber recently wrote in with a question that’s a good followup to last week’s Tip of the Week, Writing Numbers:
“When are hyphens used with numbers? Is it 13 feet or 13-feet; 12 hours or 12-hours?”
Rule: Generally, hyphenate between two or more adjectives when they come before a noun and act as a single idea.
This rule can also be applied when a number and a measurement unit taken together form an adjective, that is, when they describe another object.
A 22-inch monitor is too big for my desk.
Nurses work 12-hour shifts.
Anthony swung his five-pound hammer.
In the previous sentences, the measurements, such as 22-inch, describe specific objects, such as monitor.
When measurements are not acting as adjectives, hyphens are not needed.
Suzanne won the race by 25 yards.
Twelve hours later, she was exhausted.
Anthony’s hammer weighs five pounds.
Pop Quiz: Choose A or B.
1. A. I can’t believe she wrote a 33-page treatise on how to screw in a light bulb.
1. B. I can’t believe she wrote a 33 page treatise on how to screw in a light bulb.
2. A. I can’t believe she wrote 33-pages on how to screw in a light bulb.
2. B. I can’t believe she wrote 33 pages on how to screw in a light bulb.
3. A. Harold found a 110-year-old book at the flea market.
3. B. Harold found a 110 year old book at the flea market.
4. A. Harold found a book that must have been 110-years-old at the flea market.
4. B. Harold found a book that must have been 110 years old at the flea market.
Posted on Thursday, March 5, 2009, at 4:07 pm62 Comments on Numbers as Adjectives