小数(しょうすう)

小数(しょうすう) is a basic mathematical term taught in Japanese elementary school for numbers written with a decimal point. It contrasts with 整数(せいすう) ("whole number, integer") and 分数(ぶんすう) ("fraction"), which together form the standard inventory of number representations introduced in primary math.

Forms

• 小(しょう) ("small") + 数(すう) ("number") → 小数(しょうすう)

Common collocations

• 小数点(しょうすうてん): decimal point
• 小数(しょうすう)第(だい)一(いち)位(い) / 小数(しょうすう)第(だい)二(に)位(い): first / second decimal place
• 小数(しょうすう)に直(なお)す: to convert into a decimal
• 小数(しょうすう)で表(あらわ)す: to express as a decimal
• 小数(しょうすう)部分(ぶぶん): the fractional part of a decimal
• 循環(じゅんかん)小数(しょうすう): repeating / recurring decimal
• 有限(ゆうげん)小数(しょうすう): terminating decimal

Similar / related terms

• 整数(せいすう): integer, whole number
• 分数(ぶんすう): fraction (e.g., 1/2)
• 実数(じっすう): real number
• 小数点(しょうすうてん): decimal point
• 四捨五入(ししゃごにゅう): rounding ("round 5 up, 4 down")

Disambiguation (HOMOPHONE)

• 少数(しょうすう) "a small number, a minority" — same reading but completely different meaning. Compare:
• 小数(しょうすう)で答(こた)える: "to answer in decimal form"
• 少数(しょうすう)派(は): "the minority faction"
• The kanji difference matters: 小(しょう) ("small in size, sub-unit") vs. 少(しょう) ("few in number").

Usage

• In Japanese math classrooms, the decimal point is normally read as てん: 3.14 → さんてんいちよん.
• 小数(しょうすう) is strictly mathematical. To talk about "a few people" you need 少数(しょうすう) (different kanji) or 少(すこ)し.