There are two main types of numbers:
Cardinal Numbers — 1 (one), 2 (two) etc. (Used mainly for counting)
Ordinal Numbers — 1st (first), 2nd (second) etc. (Used mainly for putting things in a sequence)
Cardinal numbers are normally used when you:
count things: I have two brothers. There are thirty-one days in January.
give your age: I am thirty-three years old. My sister is twenty-seven years old.
give your telephone number: Our phone number is two-six-three, three-eight-four-seven. (481-2240)
give years: She was born in nineteen seventy-five (1975). America was discovered in fourteen ninety-two
Notice how we divide the year into two parts. This is the form for year up to 1999. For the year 2000 and on, we say two thousand (2000), two thousand and one (2001), two thousand and two (2002) etc.
From 1 to 12:
one, two, three, four, five, six, seven, eight, nine, ten, eleven, twelve.
From 13 to 19:
These numbers end in –teen /ti:n/
thirteen, fourteen, fifteen, sixteen, seventeen, eighteen, nineteen.
20, 30, 40, 50, 60, 70, 80, 90:
These numbers end in –ty /ti/
twenty, thirty, forty, fifty, sixty, seventy, eighty, ninety
To express tenths:
If a number is in the range 21 to 99, and the second digit is not zero, we should write the number as two words separated by a hyphen (-) after the tenth and then the unit.
You can normally create Ordinal numbers by adding -TH to the end of a Cardinal Number.
Ordinal numbers are normally used when you:
- give a date: My birthday is on the 27th of January. (Twenty-seventh of January)
- put things in a sequence or order: Liverpool came second in the football league last year.
- give the floor of a building: His office is on the tenth floor.
- have birthdays: He had a huge party for his twenty-first birthday.