How is「第3位を四捨五入」deconstructed to mean "round up to 2 decimal places"?


> 小数第２位未満に端数が生じた場合は、小数第３位を四捨五入する

I initially translated this sentence to:

> If a fraction with less than 2 decimal places is generated, round off to 3
> decimal places.

So: 2.1 ≈ 2.100

It felt somewhat _off_ , so I sought for [some sample translations
for「四捨五入」](http://www.linguee.com/english-
japanese/search?source=auto&query=%E4%BD%8D%E3%82%92%E5%9B%9B%E6%8D%A8%E4%BA%94%E5%85%A5).

>   * JP: 。。。小数点第３位を四捨五入して。。。
>
>   * EN: ...is rounded off to two decimal places...
>
>

So: 2.1 ≈ 2.10

## What?!

Why is it translated this way? Does 「四捨五入」 make the decimal places less than
the mentioned number or something else entirely? How do speakers reconcile
this?




You're taking the third place (第3位) and you're either throwing it away if it's
four or below (四捨) or you add one to the next place if it's five or above
(五入).

As a result, the third place is gone, and you're only left with two decimal
places.




You're taking the third place (第3位) and you're either throwing it away if it's
four or below (四捨) or you add one to the next place if it's five or above
(五入).

As a result, the third place is gone, and you're only left with two decimal
places.

