You should always hyphenate numbers when you are describing compound numbers between 21 and 99 (except 30, 40, 50, 60, 70, 80 and 90). A compound number is any number that consists of two words; for example, eighty-eight, twenty-two, forty-nine. Numbers higher than 99 do not need a hyphen.

Should written numbers be hyphenated?

Always hyphenate the numbers 21 to 99 when writing them out as words: I have twenty-one pairs of novelty socks. ... However, it's only 21 to 99 that we hyphenate in these large numbers. Larger round numbers, such as “one hundred,” do not require a hyphen.

Does thirty four have a hyphen?

When numbers between 21 and 99 are written out in full

one hundred and thirty-four (Note that only 'thirty-four' is hyphenated.)