Do use hyphens when writing out fractions used as adjectives Don't use hyphens when writing out fractions used as nouns (one half of the room). (two-thirds majority). What is the written form of the fraction 1/8? Becky added 1/8 cup of brown sugar to the cookie batter. A. one eighth B. one-eighth
Always use hyphens with simple fractions, unless the second half is already hyphenated. I.e. you would write "one-eighth" or "one twenty-fifth. So the answer is B.
