1.
decimal; decimal number (a number with a fractional part written after the decimal point)
A mathematical term for a number expressed in decimal form — that is, with a decimal point and a fractional part, such as 0.5, 3.14, or 12.034. Combines 小 ("small") with 数 ("number"). Beware the homophone 少数 ("small number, minority"), which is unrelated.
答えを小数で書いてください。
Please write the answer as a decimal.
小数第二位を四捨五入しなさい。
Round to two decimal places.
分数を小数に直す方法を習った。
We learned how to convert fractions into decimals.
コンピュータは小数を扱う際に丸め誤差が生じることがある。
Computers can produce rounding errors when handling decimal numbers.
小数 is a basic mathematical term taught in Japanese elementary school for numbers written with a decimal point. It contrasts with 整数 ("whole number, integer") and 分数 ("fraction"), which together form the standard inventory of number representations introduced in primary math.
FORMATION:
- 小 ("small") + 数 ("number") → 小数
COMMON COLLOCATIONS:
- 小数点: decimal point
- 小数第一位 / 小数第二位: first / second decimal place
- 小数に直す: to convert into a decimal
- 小数で表す: to express as a decimal
- 小数部分: the fractional part of a decimal
- 循環小数: repeating / recurring decimal
- 有限小数: terminating decimal
SIMILAR / RELATED TERMS:
- 整数: integer, whole number
- 分数: fraction (e.g., 1/2)
- 実数: real number
- 小数点: decimal point
- 四捨五入: rounding ("round 5 up, 4 down")
DISAMBIGUATION (HOMOPHONE):
- 少数 "a small number, a minority" — same reading but completely different meaning. Compare:
- 小数で答える: "to answer in decimal form"
- 少数派: "the minority faction"
- The kanji difference matters: 小 ("small in size, sub-unit") vs. 少 ("few in number").
USAGE NOTES:
- 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 is strictly mathematical. To talk about "a few people" you need 少数 (different kanji) or 少し.