1 基数（Cardinal Number)
在英国，基数的书写如果是千位数以上，自右至左三位数一组以逗号分开。 第一个逗号是thousand,第二个逗号是million。由于每组都是三位数，在数字练 习中，如果三位数的数字听记练好了，也就是说把百位数的数字练习好后，数字 再大也就不难掌握了。例如：
123—one hundred and twenty-three/a hundred and twenty-three
123,123— one hundred twenty-three thousand, one hundred and twenty-three
123,123,123— one hundred twenty-three million, one hundred twenty-three thousand, one hundred and twenty-three
In Britain, we use a comma (，)not a point (.)for thousands and millions. This is different from the system in some other countries.
The numbers 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900 are sometimes said as eleven hundred, twelve hundred, thirteen hundred, etc.
- 100—one hundred/a hundred
- 200—two hundred
- 300—three hundred
- 400—four hundred
- 500—five hundred
- 600—six hundred
- 700一seven hundred
- 800—eight hundred
- 900—nine hundred
- 212—two hundred and twelve
- 338—three hundred and thirty-eight
- 402—four hundred and two
- 509—five hundred and nine
- 627—six hundred and twenty-seven
- 741—seven hundred and forty-one
- 853—eight hundred and fifty-three
- 999—nine hundred and ninety-nine
2 序数（Ordinal Number )
The numbers 1, 2, 3 at the end are usually written as 1st ( first), 2nd ( second ), 3rd (third ), also in 21st (twenty-first), 31st (thirty-first), 22nd (twenty-second ), 23rd (twenty-third ).
The other numbers are written with th after them: 4th, 6th, 20th, 27th, 60th.
For numbers ending in 1 add st, for those ending in 2 add nd, for those ending in 3 add rd; for all others add th.
- 35 th—thirty-fifth
2.2 序数常用于日期表达 在英国，日期有两种写法：
In numbers only: day/month/year. So 5/1/2009 = 5th January 2009, not May 1st 2009.
In numbers and words: day/month/year—20th December 2009; or month/day/ year—December 20th 2009. When you say the dates, 20/12/2009 can be the twentieth of December 2009 or December the twentieth 2009.
Different cultures have different lucky and unlucky numbers. In Western countries, thirteen is an unlucky number. Some hotels do not have a thirteenth floor. In China, four is an unlucky number because it sounds like the word for “death”. Double sixes ( 66 ) is very lucky because it sounds like “everything goes well”. Eight is another lucky number because it sounds like “you will make a fortune”. In Thailand, three and nine are good numbers. People in India say odd numbers ( 3, 5, 7, 9. . . ) are lucky.
3 小数（Decimal Fraction)
In decimal fractions, an has two names: It’s called naught if it comes before the decimal point; it’s pronounced “oh” after the point.
Numbers before the decimal point are said normally: one, two, ten, thirteen, twenty-four, two hundred, etc. After the point we say each number by itself, e.g., 1.23 we say one-point-two-three.
- 0.01 —naught-point-oh-one
4. 百分比（Percentage )
We use percentages when we want to express a number more simply. Percentage means the number of X per 100. For example, if 50 students are in the class, and 25 of them are boys, we can say 50% of the students are boys. “Percent”, is said after the number:
- 20%—twenty percent
- 26%—twenty-six percent
- We can use “％” with decimals:
- 7.02%—seven-point-oh-two percent
- 0.51%—naught-point-five-one percent