小数、分数、百分数和运算符号

1. 小数表示法

(1) 小数的读法

小数点左边的数通常按基数词读，若为三位以上的数，也可按编码式读法读出，即将数字单个读出；小数点右边的数通常按编码式读法单个读出。如：

6.86 six point eight six

14.15 fourteen point one five

345.456 three four five point four five six

或 three hundred and forty－five point four five six

(2) 小数中“0”的读法

“0”在小数中通常读作nought（英）或zero（美），也可读作字母o。如：

0.08 （nought）point nought eight 或 （zero）point zero eight

9.07 nine point o seven

2. 百分数表示法

百分数中的百分号％读作percent。如：

6% 读作 six percent

0.6% 读作 （nought） point six percent

500% 读作 five hundred percent

3. 倍数表示法

倍数表示方法很多，如：

This room is four times as big as mine.

这个房间是我房间的四倍。

This room is three times larger than that one.

这个房间比那个房间大两倍。

The output of coal has doubled. 煤的产量增加了一倍。

My aunt is as old again as I am. 我姑姑年龄比我大一倍。

Productivity is increased three fold.

生产效率提高了两倍。

The volume of the Sun is about 1,300,000 times that of the Earth.

太阳的体积约为地球的1300000倍。

4. 加减乘除式的读法

6+5＝11   Six plus five is eleven 或 Six and five is eleven. 
11-6＝5   Eleven minus six is five. 或 Six from eleven is five. 
4×5＝20   Four multiplied by five is twenty.或 Four times five is twenty. 
20÷4＝5   Twenty divided by four is five. 或 Four into twenty goes five. 
15:5＝3   The ratio of fifteen to five is three. 
32        Three squared is nine. 
23        Two cubed is eight. 
24        The fourth power of two is sixteen. 
X^(1/2)=Y The square root of X is Y. 
X^(1/3)=Y The cubic root of X is Y. 
a ＞ b     a is more than b. 
a ＜ b     a is less than b. 
a ≈ b     a approximately equals to b. 
a ≠ b     a is not equal to b. 

5. 分数表示法

(1) 较小分数的一般读写方法。如：

1/3 one-third    2/3 two-thirds     3/5 three-fifths

(2) 较复杂分数的简明读写方法。如：

22/9    twenty-two over nine
a/b     a over b 或 a divided by b 
43/97   forty-three over ninety-seven 

(3) 整数与分数之间须用and连接。如：

four and a half            nine and two fifths 

(4) 分数用作前置定语时，分母要用单数形式。注意下列写法与读法。如：

a one-third mile　1/3英里      a three-quarter majority　3/4的多数