What numbers between 20 and 99 are not hyphenated?

Answer 1

Generally, when spelt out in words in English, you hyphenate the numbers between 20 and 99 which have digits other than 0 in the units column - for example, twenty-one, twenty-two, twenty-three.... ninety-eight, ninety-nine.

Answer 2

All numbers between 21 and 99 are not hyphenated, except for the multiples of ten (30, 40, 50, etc.)