# Ordinal Numbers

Imagine that you are on a list and you want to know where you are standing. To refer to that number, we use 'ordinal numbers.'

## What Are Ordinal Numbers?

Ordinal numbers are numbers used to indicate the position or order of something in a list or sequence. They are used to rank and order items in a series.

## How to Write Ordinal Numbers: 1-10

Most of the numbers get 'th' at the end to change to an ordinal number, except for the first three numbers:

Written Numeral
first 1st
second 2nd
third 3rd
fourth 4th
fifth 5th
sixth 6th
seventh 7th
eighth 8th
ninth 9th
tenth 10th

Using ordinal numbers in a sentence

### Exceptions in Spelling

Please note that apart from 1st, 2nd, and 3rd, the spelling of some of the numbers changes when 'th' is added to them.

• five + th → fifth
• eight + th → eighth
• nine + th → ninth

## How to Write Ordinal Numbers: 11-20

Written Numeral
eleventh 11th
twelfth 12th
thirteenth 13th
fourteenth 14th
fifteenth 15th
sixteenth 16th
seventeenth 17th
eighteenth 18th
nineteenth 19th
twentieth 20th

### Exceptions in Spelling

As you can see in the table above, some of the numbers change form when 'th' is added to them.

• twelve + th → twelfth
• twenty + th → twentieth

## How to Write Ordinal Numbers: Compound

For compound ordinal numbers, use this structure:
first part (in cardinal form) + hyphen + second part (ordinal form)

Written Numeral
twenty-first 21st
twenty-second 22nd
twenty-third 23rd
twenty-fourth 24th
twenty-fifth 25th
twenty-sixth 26th
twenty-seventh 27th
twenty-eighth 28th
twenty-ninth 29th

## How to Write Ordinal Numbers: The Tens

For the tens, note that the letter 'y' at the end of the cardinal numbers, turns into 'ie' in ordinal numbers.

Written Numeral
tenth 10th
twentieth 20th
thirtieth 30th
fortieth 40th
fiftieth 50th
sixtieth 60th
seventieth 70th
eightieth 80th
ninetieth 90th

## How to Write Ordinal Numbers: The Hundreds

To write a number from 100 to 999 in ordinal form, start by writing the number of hundreds. If there is nothing left over, add the suffix '-hundredth' to the end of the number. For example, '500' becomes 'five hundredth'.
If there are additional numbers beyond the hundreds, write the word 'hundred' followed by the rest of the numbers in ordinal form.

Written Numeral
one hundred first 101st
one hundred second 102nd
one hundred third 103rd
two hundred seventy-fifth 275th
three hundredth 300th
five hundred eightieth 580th
nine hundred ninety-eighth 998th

## Roman Numerals

Roman numeral system numbers originated in ancient Rome where they used the letters I, V, X, L, C, D, and M to write numbers. Each of these letters represents a number: I for 1, V for 5, X for 10, L for 50, C for 100, D for 500, and M for 1000.
We can put the symbols in descending order from left to right and add numbers together. If we add all of the numbers' values together, we get the total value. For example:

XXVI is 10 + 10 + 5 + 1 = 26

XXXIII is 10 + 10 + 10 + 1 + 1 + 1 = 33

We can also put a symbol with a smaller value on the left side of the one with a larger value and subtract the value of the smaller symbol from that of the larger symbol to get the total value. For example:

IV is 5 – 1 = 4

IX is 10 - 1 = 9

### Tip!

Note that none of the Roman numerals can come together more than three times. For example, to show 40, we cannot write XXXX, instead, we use XL which means 10 is subtracted from 50.

## Ordinal Numbers: Function

Ordinal numbers are used to indicate the position or order of things or objects in a sequence. Their purpose is to arrange different items in a specific order based on their position or standing. When objects or things are placed in a particular order, the counting procedure requires labeling them with numbers, and ordinal numbers help to tell their precise position or place them in order within a group.
Ordinal numbers are used in many different contexts, from everyday life to sports games, mathematics, and science. They are essential for organizing data, such as ranking sports teams, listing items in a menu or catalog, or describing events in a story or timeline. Let's see some examples:

Steven came third in the race.

The fifth book from the left is an amazing book.

Newton's first law states that every object will remain at rest or in uniform motion in a straight line unless compelled to change its state by the action of an external force.

## Ordinal Numbers Vs. Cardinal Numbers

The difference between cardinal and ordinal numbers is that we use cardinal numbers to count or indicate the quantity of things, therefore, any natural number is considered cardinal. For example:

Three students

Five pencils

But ordinal numbers are used to express the position or order of objects. For instance:

Second car

10th birthday

## Ordinal Numbers and Cardinal Numbers Together

Ordinal and cardinal numbers regularly appear together, even to quantify the same object. When a cardinal number and an ordinal number modify the same noun, the ordinal number always comes first, before the cardinal number:

The first two players who ran in the field made the audience to gasp.

The second three players were practically invisible.

We also should know that two ordinal numbers cannot appear back to back. We cannot say 'the first second race', unless there is a word or punctuation between the two ordinal numbers.

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