How to say numbers in English?

British English speakers always use and before the tens in a number.

• 310 = three hundred and ten
• 455 = four hundred and fifty-five

In American English, and is optional and can be dropped.

• 525 = five hundred and twenty-five or five hundred twenty-five
• 398 = three hundred and ninety eight or three hundred ninety-eight

When we write large numbers, we divide them into groups of three figures, by separating them off with commas. Note that full stops are not used in this case.

• 386,545 (NOT 386.545)
• 32, 128

Note that commas are not always used to separate four digit numbers, and they are never used in dates.

I was born in 1979. (NOT I was born in 1,979.)

We can say a hundred or one hundred, a thousand or one thousand.

• My grandmother lived for a hundred years. OR My grandmother lived for one hundred years.
• Can you lend me a thousand dollars? OR Can you lend me one thousand dollars.

Note that the forms with one are more formal.

We cannot use a in the middle of a number. Instead we use one.

• 3100 = three thousand and one hundred (NOT Three thousand and a hundred)

Round numbers between 1,100 and 1,900 are often expressed in hundreds. This is common in an informal style.

• They are asking eleven hundred dollars for that laptop. OR They are asking one thousand, one hundred dollars for that laptop.