Numbers
If math describes how the world works, numbers are the alphabet that makes math possible. In this lesson, we will discover all about them.
What are Numbers?
Numbers are mathematical symbols used to express quantity. We use numbers to count, label, and measure people or objects. We can use numbers everywhere, we use them to tell dates, phone numbers, etc.
Numbers: Types
There are two main groups of numbers in English:
Cardinal Numbers
Cardinal numbers (also called cardinals) are used to count the number of people, animals, or things, such as two, six, twelve, or five hundred. They show how many of those things or people there are.
Placement
Cardinal numbers are commonly used as determiners. In other words, they are typically used before nouns. For example:
I love my pets. I have
When used as a determiner, they can also take predeterminers such as articles or possessive determiners before them. For example:
My
We can use cardinal numbers with the following structure:
cardinal numbers + of + determiners
Tip!
Cardinal numbers can also be used as nouns.
People came to the theater in
Numbers Bigger Than Twenty
If you want to write numbers bigger than twenty, you should use a hyphen between parts of the compound number. In other words, hyphenate all compound numbers between twentyone and ninetynine. For example:
Numbers Bigger Than 100
With numbers bigger than 100, you should use a hyphen between the compound numbers after the word 'and'.
For 100, we can either use the definite article 'a' or use 'one'.
eight hundred and
In American English, people normally do not use the word 'and':
three hundred fiftysix
Numbers Bigger Than 1,000
When writing numbers larger than 1,000, use a hyphen between compound numbers and include the word 'and'. You can use either the indefinite article 'a' or 'one' for 1,000. Also, remember to use a comma to separate every three digits, such as '80,000'.
In American English 'and' is mostly not used.
five thousand (and) two hundred (and) thirtyfour
Number 0
The number 0 has many names:
 in telephone numbers, codes, etc. →
oh  in measurements and temperature →
zero  in British English →
nought  in sports commentary →
nil  in tennis →
love
What Are Ordinal Numbers?
Ordinal numbers are used to show the order of things on a list or in a row, that's why we call them ordinal. Here are a few examples:
This is the
She is the
How to Make Ordinal Numbers?
Most of the numbers get th at the end to change to an ordinal number, except the first three numbers. Check out the table below:

twentie 

thirtie 

fortie 
four 
fiftie 
fif 
sixtie 
six 
seventie 
seven 
eightie 
eigh 
ninetie 
nin 
hundred 
ten 
thousand 
Now let us take a look at the numbers that have more than one part:
twentyfirst (21st)  one hundred and thirtyfirst (131th) 
twentysecond (22nd)  two hundred and fortyfifth (245th) 
twentythird (23rd)  three hundred and fiftyseventh (357th) 
When Do We Use Ordinal Numbers?
Ordinal numbers are used in many different contexts:
 fractions
 Roman numerals
 telling the dates and talking baout centuries
Fractions
A fraction is a particular form of writing numbers. Fractions are used to express a part of a whole or a collection. Here are some examples:
fraction
Roman Numerals
The letters I, V, X, L, C, D, and M of the Latin alphabet were used to express numbers in ancient Greece. Nowadays. we still use them in some cases. Let's see an example:
Alice III → Alice the
Roman number
Telling the Dates and Century
My birthday is on June the
telling the dates
The castle was built in the
talking about centuries
How to Write Ordinal Numbers
When writing ordinal numbers in number form, use the last two letters of the ordinal form in a smaller form after the cardinal number. For example:
 first = 1st
 second = 2nd
 third = 3rd
 fourth = 4th
Talking about Money & Prices
Each country has its own system of money, such as Dollar in the USA, Pound in the UK, and Euro in European countries. There are different ways to say the prices, Let's go through the common ones:
One, Two, and Three Digit Prices
$4.20 → Fourtwenty
just say the numbers
$4.20 → Four dollars (and) twenty
saying 'and' is more common in British English, and Americans usually don't say it.
$4.20 → Four dollars (and) twenty cents
this is the more formal
$580 → five hundred (and) eighty dollars
if the price is an exact number of pounds, euros or dollars we should say it completely.
£100 → a hundred pounds
with prices beginning with 'one' we could use 'a' instead of 'one'.
Four Digit Prices
Mostly, fourdigit numbers are read in the same way as we have explained above, but there are some exceptions as well.
$1250 → a thousand two hundred fifty
$5260 → five thousand two hundred sixty
$
we can also say a thousand five hundred