Unit 8.1
Cardinal numbers: Decimals, Tens and Hundreds
Introduction
Cardinal numbers give information about how many people or things there are.
Decimals are the smallest of the numbers, being the result of fractions. Ten numbers go from 1 to 99. Hundred numbers go from 100 to 999.
Form
Decimal numbers are the result of a fraction.
- They normally have a comma or a point between the whole number and the decimals.
Ten numbers have ten as its base. Despite, the numbers from 1 to 9 are commonly called unities.
- Plain form: number + 0
- They have specific names from 0 to 20
- From 20 to 99 the numbers follow a pattern to name them: Using a hyphen in between the ten number and the unit.
| Unities from 1 to 9 | Tens from 11 to 19 | Tens from 10 to 90 | Tens + unities |
| one | eleven | ten | twenty-one |
| two | twelve | twenty | twenty-two |
| three | thirteen | thirty | twenty-three |
| four | fourteen | fourty | twenty-four |
| five | fifteen | fifty | twenty-five |
| six | sixteen | sixty | twenty-six |
| seven | seventeen | seventy | twenty-seven |
| eight | eighteen | eighty | twenty-eight |
| nine | nineteen | ninety | twenty-nine |
The hundred numbers have one hundred as its base.
- Plain form: number + 00
- Their name is: how the number in the beginning is called + hundred
- 100 can be called ‘one hundred’ or ‘a hundred’
- If there are more numbers after the hundred number, they need to be mentioned as normal (ten number). Sometimes, we use ‘and’ in between the hundred number and the ten number.
- From 100 to 999
| Hundreds from 100 to 900 | Hundreds + Unities | Hundreds + Tens |
| one hundred | one hundred and one | one hundred and ten |
| two hundred | one hundred and two | one hundred and twenty |
| three hundred | one hundred and three | one hundred and thirty |
| four hundred | one hundred and four | one hundred and forty |
| five hundred | one hundred and five | one hundred and fifty |
| six hundred | one hundred and six | one hundred and sixty |
| seven hundred | one hundred and seven | one hundred and seventy |
| eight hundred | one hundred and eight | one hundred and eighty |
| nine hundred | one hundred and nine | one hundred and ninety |
Example
DECIMALS:
- 567/100 = 5,67
- Five point sixty-seven
TEN NUMBERS:
- 10 (ten)
- 25 (twenty-five)
HUNDRED NUMBERS:
- 100 (one hundred)
- 871 (eight hundred seventy-one)
Use
We normally use the singular form of the numbers - when we are naming a concrete figure.
We use the plural form when we are not speaking about a concrete number, but in general terms. We don’t even use a whole number for that:
- Hundreds of + noun (“There were hundreds of adolescents in that party”)
In formal writing it is better to write the number in letters when it is a short figure.