书写英语数字时几条约定俗成的规则

一、1至10用单词表示，10以上的数目用阿拉伯数字（也有的以100为界限）。  
The traditional pattern of classroom experience at the college level brings the professor and a group of 20 to 30 students together for a 45-to-50-minute class session two or three times a week.  


二. 人数用阿拉伯数字表示，但不定数量、近似值用单词表示较恰当。  
There are 203817 voters on the electoral rolls, nearly thirty thousand voters took part in this election.  


三. 遇到日期、百分比、带单位的特殊数字，通常用阿拉伯数字。  
3rd March l991或3 March l991； a discount of 5 percent ； order 2 pounds of steak
如果涉及的数目和单位是不定数，可用单词表示。  
about five miles per hour;  at least ten yards away; one hundred times


四. 在科技文章中，数字频繁出现，用阿拉伯数字比用单词陈述更有利。  
The new engine has a capacity of 4.3 liters and a power output of 153 kilowatts at 4400 revolutions per minute.  


五. 句首不用阿拉伯数字，句末要尽量避免用阿拉伯数字。  
4th July (The fourth of July)is an important date in American history.  
60％ (Sixty per cent) profit was a reported．  
1345 kilograms force was applied at the center point of the bar.  
可改成When tested, a force of l345 kg was applied...  


六. 遇到分数，可用带连字符的单词表示.