When do you hyphenate numbers? I hate to admit it, but it’s not simple. I will try to sort it out though, into something that’s easy enough to remember.

1 2 3 4 5 6 7 8 9 0

For a start, with numbers, the general rule is “twenty-one through ninety-nine are hyphenated; others are open.”

thirty-five

two thousand twenty-two

one hundred seventy-five

For simple fractions, here are some examples:

one-half

two-thirds

three-quarters

one sixty-fourth

two and five-sixths

Hyphenate, if you use the fraction as a noun (one-half), adjective (a two-thirds majority), or adverb (three-quarters done), except when the second element is already hyphenated (a one twenty-fifth share). Also if you have a whole number followed by a fraction, only hyphenate the fraction (two and three-quarters).

When a number is used with an abbreviation, it is always open (no hyphen).

a 5 lb. roast

a 4 ft. high fence

When a number is used with a noun, hyphenate before the noun, otherwise leave it open.

a three-hundred-yard race, but the race was three hundred yards long

a six-foot-two athlete, but the athlete was six foot two

a two-and-a-half-foot stick, but the stick was two and a half feet.

a two-and-three-quarter-inch stick, but the stick was two and three-quarters of an inch

And lastly, we have ordinals, basically the same rule.

a second-floor condo, condo on the second floor

third-row seat, seat in the third row

second-to-last candidate, candidate came second to last

I hope you don’t have a first-class headache after this intense session. If you do, I hope your medications are first class and you’ll feel better soon. Maybe it will be a half-hour remedy and you’ll feel better in half an hour.