Hyphen In Compound Numbers

When writing a compound number – any number made up of two words – we use a hyphen in between them. This applies to any number between 21 and 99. Numbers higher than ninety-nine don’t require a hyphen.

Forty-four

Twenty-seven

Fifty-six bottles of pop on the wall, fifty-six bottles of pop….

No, I won’t party “like it’s nineteen ninety-nine”.

This rule applies even if these numbers are preceded by other numbers.

One hundred and thirty-three

Six thousand and seventy-two.

One hundred million, forty-four thousand, nine hundred and eighty-five

The rule also applies if a number between 21 and 99 is being used as an adjective.

Ninety-nine thousand, nine hundred and ninety-nine.

Seventy-five billion dollars is not a lot of money when you’re researching space.

If twenty-two million people died, it would be called “a disaster”; if twenty-two million trees die, we call it “the pulp-and-paper industry”.