Generally, common fractions (simple fractions) should be written out and hyphenated: Two-thirds One-fourth Three-fifths Mixed fractions are commonly expressed as decimals to avoid confusion: 7.5 (instead of “seven and one-half” or “7 1/2”) 10.75 (instead of “ten and three-fourths” ...
Many style guides have distinct rules for fractions. Generally, common fractions (simple fractions) should be written out and hyphenated: Two-thirds One-fourth Three-fifths Mixed fractions are commonly expressed as decimals to avoid confusion: 7.5 (instead of “seven and one-half” or “7 1/2...