21st is usually hyphenated when spelt. Dictionaries list it as 'twenty-first'.
However, as a book/article title, or in company names, it is sometimes written as Twenty First ... as in 'Twenty First Century Poets', but, as this could be interpreted as meaning a book about 1st century poets, a hyphen would remove any ambiguity e.g. written as 'Twenty-first Century Poets' or 'Twenty-First Century Poets' (unless, of course, the book is actually about 1st century poets, in which case a better title would be 'Twenty First-Century Poets'!)
Yes. An ordinal number (first, second) is hyphenated when used as an adjective or adverb. While numbers larger than 10 may be properly replaced by the numeral, any written-out numbers are also hyphenated. Example : "It was the twenty-fifth anniversary." Example : "It was the one hundred and twenty-fifth anniversary." Example : "There were thirty-one runners. I finished twenty-fifth." Example : "There were 31 runners, and I finished 25th."
The ordinal number 21st is written out "twenty-first."twenty-first
It is neither. The word is hyphenated, like so: twenty-third.
The number 428 is "four hundred twenty-eight." (It is hyphenated when used as an adjective in English.)
It is hyphenated, as asked, eighty-four. Numbers from 21 to 99 are hyphenated when spelled out, as are combined ordinal forms such as one hundred-thousandth, one fifty-fifth, and so forth.
words are only hyphenated when they have a separate meaning when separated than they do when hyphenated
The ordinal number 21st is written out "twenty-first."twenty-first
This is in two words, "twenty fourth," hyphenated in the US as twenty-fourth (24th).
It is neither. The word is hyphenated, like so: twenty-third.
The twenty fifth sultan of the Ottoman Empire was Osman III.
twenty-seven
4
The Twenty-fifth Amendment make provision for presidential succession.
The Twenty-fifth Anniversary Anthology was created on 2006-01-24.
The spelling would be "one twenty-fourth" or 1/24.(the denominator is separately hyphenated, as in twenty-one twenty-fourths, 21/24)
That depends on what you mean: twenty add one fifth is 20 + 1/5 = 20 1/5 twenty, add one fifth (of twenty) is 20 + 1/5 * 20 = 20 + 4 = 24
The twenty-Fifth Amendment
Twenty percent is the equivalent of one fifth.