四捨五入

ししゃごにゅう

rounding up (fractions)

JLPT N2

Character Breakdown

Understanding 四捨五入 (Rounding)

The term 四捨五入 (ししゃごにゅう) refers to the mathematical process of rounding numbers, especially decimals, to the nearest integer or specified digit. It literally means "four discard, five enter," indicating that digits 4 and below are dropped, while 5 and above are rounded up.

Usage in Daily Life

This term is commonly used in contexts like financial calculations, measurements, and statistics where precise decimal values are simplified for convenience. For example, when calculating prices or salaries, numbers are often rounded using 四捨五入.

Common Collocations and Patterns

  • 四捨五入する: to round a number
  • 四捨五入して〜になる: after rounding, it becomes ~
  • 四捨五入のルール: rounding rules

These collocations help express the action and rules of rounding clearly.

Register and Nuance

四捨五入 is a neutral, formal term used in both spoken and written Japanese, especially in academic, business, and technical contexts. It is not casual slang.

Common Learner Mistake

Learners sometimes confuse 四捨五入 with simply truncating decimals (切り捨て) or always rounding up (切り上げ). Remember, 四捨五入 rounds down if the digit is 4 or less, and rounds up if 5 or more.

Example Sentences

このけいさんではしょうすうてんいかをししゃごにゅうしてせいすうにします。

In this calculation, we round off the decimal part to get an integer.

ししゃごにゅうすると、さんてんろくはよんになります。

When rounding, 3.6 becomes 4.

きゅうりょうのけいさんでししゃごにゅうをつかうことがおおいです。

Rounding is often used in salary calculations.