This question has been bothering me. Is twenty five proper or twenty-five?

twenty-five

Yes, use a hyphen between words for the names of numbers between 21 and 99.

The question you have is regarding the usage of numbers in writing. Specifically, you would like to know if it is more appropriate to write "twenty five" as one word (twentyfive) or as two words (twenty-five).

In this case, the correct and widely accepted format is to use a hyphen between the words "twenty" and "five," making it "twenty-five."

Hyphens are commonly used in compound numbers from 21 to 99 (such as twenty-five, sixty-seven, or ninety-nine) to indicate a single entity. It helps to avoid confusion when reading the number.

To confirm this information, you can consult a style guide or a grammar reference book, such as "The Chicago Manual of Style" or "The Associated Press Stylebook." These resources provide comprehensive guidelines on various writing conventions and can serve as reliable references for questions related to punctuation, grammar, and style.