「四捨五入」的英文怎樣叫?

你可以寫standard rounding/symmetric rounding。Rounding的意思是除整，通常有三個方法：standard rounding (=1-4 round down, 5-9 round up)，rounding up always(=1-9 round up)，rounding down always (=1-9 round down)。這個standard rounding方法其實是「不公平」，因為1-4只有四個數目字，而5-9郤有五個，所以向上入的機會較多。

一些軟件會用都的是unbiased rounding，1-4與6-9的方法跟以上的一樣，不過5就要看前一個數目字是單還是雙數（單向上入，雙向下捨）。如果你要兩個小數位：
1.041 > 1.04 --- 1.051 > 1.05
1.044 > 1.04 --- 1.054 > 1.05
1.045 > 1.04 --- 1.055 > 1.06
1.046 > 1.05 --- 1.056 > 1.06
1.049 > 1.05 --- 1.059 > 1.06
這樣，有一半的5會向下捨（02468），而另一半（13579）則向上入。

to round up or down / to round off

Round off the last number, forward as 1 if it is 5 or more, make it
as zero if it is 4 or less.
(調整最後的數字,若是 5 或大於5, 就進位加一, 若是4 或低於4, 變為零。)

forward===進位
以上是符合四捨五入的說法

But, we can say : round something up/down, i.e. increase/decrease
(a figure, price, etc) to the nearest whole number.
e.g. A charge of $1.90 will be rounded up to $2, and one of $3.10
rounded down to $3.
(把$1.90的費用上調為$2, 把$3.10下調為$3 )


2008-06-22 22:12:51 補充：
tintin852's advice is helpful. I have got to know that standard rounding represents 四捨五入.
But, we need to add some more explanation in case people might not understand.

Rounding off =四捨五入
In this method, we estimate a number correct to a degree of accuracy.
Eg:132=130(because 2 little than 5)
1.38=1.4(because 8is greater thanor equal to5)



rounding up and down=上捨入和下捨入
而不是四捨五入

round down and round up!
例如: can you agree rounding down and rounding up the price of the goods?
你是否可以接受將貨物的價格四捨五入?

Four sheds five enter