Cardinal Numbers

Introduction

Cardinal numbers are basic numbers. We use them to count and to indicate how much of something there is.

Writing of Cardinal Numbers

1 one 11 eleven 21 twenty-one 31 thirty-one
2 two 12 twelve 22 twenty-two 40 forty
3 three 13 thirteen 23 twenty-three 50 fifty
4 four 14 fourteen 24 twenty-four 60 sixty
5 five 15 fifteen 25 twenty-five 70 seventy
6 six 16 sixteen 26 twenty-six 80 eighty
7 seven 17 seventeen 27 twenty-seven 90 ninety
8 eight 18 eighteen 28 twenty-eight 100 one hundred
9 nine 19 nineteen 29 twenty-nine 1,000 one thousand
10 ten 20 twenty 30 thirty 1,000,000 one million

Tens

In British English we put an and between the hundreds and the tens (110). If there are no tens (2,001), we put the and before the single digits. We can leave the and out in American English.

Example:
110 – one hundred and ten
(American English: one hundred ten)
1,250 – one thousand, two hundred and fifty
(American English: one thousand, two hundred fifty)
2,001 – two thousand and one
(American English: two thousand one)

Hundreds

We put a or one before the number 100, but only at the beginning of a number (a is colloquial).

Example:
100 – a hundred/one hundred
2,100 – two thousand, one hundred

Thousands and Millions

The same rule applies for a and one with thousands and millions as with hundreds.

Example:
1,000 - a thousand/one thousand
201,000 - two hundred and one thousand

To note:

Thousands are separated by commas in English.

Example:
57,458,302 – fifty-seven thousand, four hundred and fifty-eight thousand, three hundred and two

One Billion, Trillion etc.

The words billion, trillion etc. refer to different numbers in different languages. In English, one billion has 9 zeroes and one trillion has 12 zeroes.

Example :
one million = 1,000,000 (6 zeroes)
one billion = 1,000,000,000 (9 zeroes)
one trillion = 1,000,000,000,000 (12 zeroes)
one quadrillion = 1,000,000,000,000,000 (15 zeroes)
one quintillion = 1,000,000,000,000,000,000 (18 zeroes)