Are Numbers Adjectives? Do They Need a Hyphen?

Here is a common grammar question:

“When do you use hyphens with numbers? For example, is it correct to say 3 feet or 3-feet? And would you write 2 hours or 2-hours?”

Here is the rule to learn: You need a hyphen between two or more adjectives that are used before a noun and act together as a single idea.

This rule also applies to putting a number and a measurement unit together to form an adjective.

For example:

A 50-inch television is too big for this room.

Doctors work 12-hour shifts.

Brian swung the ten-pound sword.

In the sentences above, the measurements, such as 50-inch, describe specific objects, such as television.

When measurements are not being used as adjectives, then hyphens are not needed.

For example:

Haley won the race by 15 yards.

Nine hours later, he was exhausted.

Danielle’s bag weighs eight pounds.

Let’s test your knowledge with a pop quiz! Choose A or B.

1. A. I don’t understand why he wrote a 22-page paper on that boring topic.
2. B.  I don’t understand why he wrote a 22 page paper on that boring topic.
3. A. I don’t understand why he wrote 22-pages on that boring topic.
4. B. I don’t understand why he wrote 22 pages on that boring topic.
5. A. Ashley found a 101-year-old statue at the garage sale.
6. B. Ashley found a 101 year-old statue at the garage sale.
7. A. Ashley found a statue that must have been 101-years-old at the garage sale. 
8. B. Ashley found a statue that must have been 101 years-old at the garage sale. 

Answer Key;

1. A.
2. B.
3. A.
4. B.

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