How to say "fraction" in Japanese

• 小数しょうすうJLPT N2approx.Common
  no-adjectiveCovers a fraction as part of a whole expressed with a decimal point; in mathematics it is the word for decimals, so it is not the term for fractions written as one number over another.
• 分数ぶんすうJLPT N2approx.Common
  no-adjectiveThis is the word for the mathematical sense: a quantity expressed as one number over another. For arithmetic and mathematics contexts, it is the natural choice for English 'fraction'.
• 端数はすうCommon
  no-adjectiveUsed for a fraction in the sense of a leftover or odd amount — the small remainder left when a total is rounded — rather than the mathematical fraction.
• 半端はんぱJLPT N1approx.Common
  nounRefers to an odd sum or amount that does not come to a round figure; for the mathematical sense of 'fraction' it is not the word you want.

For the mathematical sense use 分数, or 小数 when the fraction is written as a decimal; for leftover or odd amounts, especially of money, choose 端数 or 半端.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• 小数しょうすうfraction (part of)
• 分数ぶんすうfraction
• 端数はすうfraction
• 端はしたfraction
• 留分りゅうぶんfraction (e.g. in distillation)
• 半端はんぱfraction
• フラクションfraction
• 分画ぶんかくfractionation