Large numbers should be read in groups of hundreds. Note that after a number, hundred, thousand, million and billion have no –s.
- Two hundred (NOT Two hundreds)
- He is worth ten billion. (NOT He is worth ten billions.)
If there is no number before these words, we usually use their plural forms. Of is also used.
- He is worth billions of dollars.
In British English, we use and before the tens in a number.
- 240 – Two hundred and forty
In American English, and can be dropped.
- 350 – Three hundred and fifty OR Three hundred fifty
- 6,374 – Six thousand three hundred and seventy four
In writing, large numbers are usually divided into groups of three with commas. Note that full stops are not used in this way.
- 5,385 (NOT 53,85) (NOT 5.385)
Commas are not used in years and they can be left out in four-digit numbers.
- She was born in 1972. (NOT She was born in 1,972.)
- 3874 OR 3,874
We can say a hundred or one hundred, a thousand or one thousand.
- Few people manage to live for a hundred years.
- You have to give me one thousand dollars.
Billion and million
A million is a thousand thousand. It has got 6 zeroes. In American English, a billion is a thousand million. In British English, too, a billion is now a thousand million. However, in British English, a billion used to be a million million.