Why the 21 part uses a hyphen
Compound numbers from 21 through 99 join the tens word and the ones word with a hyphen. In 21, the 21 part combines twenty and one, producing twenty-one.
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21 in words is twenty-one.
| Style | Words |
|---|---|
| American English | twenty-one |
| British English | twenty-one |
Compound numbers from 21 through 99 join the tens word and the ones word with a hyphen. In 21, the 21 part combines twenty and one, producing twenty-one.