CARDINAL and ORDINAL NUMBERS
The cardinal numbers (one, two, three, etc.) are adjectives referring to quantity, and the ordinal numbers (first, second, third, etc.) refer to distribution.
Number 
Cardinal 
Ordinal 
1

one

first

2

two

second

3

three

third

4

four

fourth

5

five

fifth

6

six

sixth

7

seven

seventh

8

eight

eighth

9

nine

ninth

10

ten

tenth

11

eleven

eleventh

12

twelve

twelfth

13

thirteen

thirteenth

14

fourteen

fourteenth

15

fifteen

fifteenth

16

sixteen

sixteenth

17

seventeen

seventeenth

18

eighteen

eighteenth

19

nineteen

nineteenth

20

twenty

twentieth

21

twentyone

twentyfirst

22

twentytwo

twentysecond

23

twentythree

twentythird

24

twentyfour

twentyfourth

25

twentyfive

twentyfifth

26

twentysix

twentysixth

27

twentyseven

twentyseventh

28

twentyeight

twentyeighth

29

twentynine

twentyninth

30

thirty

thirtieth

31

thirtyone

thirtyfirst

40

forty

fortieth

50

fifty

fiftieth

60

sixty

sixtieth

70

seventy

seventieth

80

eighty

eightieth

90

ninety

ninetieth

100

one hundred

hundredth

500

five hundred

five hundredth

1,000

one thousand

thousandth

100,000

one hundred thousand

hundred thousandth

1,000,000 
one million 
millionth 
Examples
 There are twentyfive people in the room.
 He was the fourteenth person to win the award since 1934.
 Six hundred thousand people were left homeless after the earthquake.
 I must have asked you twenty times to be quiet.
 He went to Israel for the third time this year.
Fractions and decimals
Said 
Written 
Said 
half

0.5

point five

a quarter

0.25

point two five

three quarters

0.75

point seven five

Percentages
Written 
Said 
25%

twenty five percent

50%

fifty percent

75%

seventy five percent

100%

a/one hundred percent

Units
Written 
Said 
$1,200

one thousand two hundred dollars

£16,486

sixteen thousand four hundred and eightysix pounds

545kms

five hundred and fortyfive kilometres

$25.35

twentyfive dollars thirtyfive

Years
Written 
Said 
1988

Nineteen eightyeight

1864

Eighteen sixtyfour

1999

Nineteen ninetynine

How to say '0'
nought

used in mathematical expressions and decimals:
'nought times three equals nought'
0.3 = 'nought point three' (or 'point three')
0.03 = 'point nought three'

zero

used in scientific expressions, especially temperatures:
20^{o}C = minus twenty degrees or
twenty degrees below zero
also used to mean 'the lowest point':
'The heavy rain reduced visibility to zero'

'o' (the letter)

used in telephone numbers:
0171 390 0062 = 'o one seven one three nine o double o six two'

nil/nothing

used to express the score in games such as football:
2  0 = 'two nil' or 'two nothing'
