# 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

### 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.

- fi
ve + th → fifth - eigh
t + th → eighth - nin
e + th → ninth

## How to Write Ordinal Numbers: 11-20

Written | Numeral |
---|---|

eleventh |
11 |

twelfth |
12 |

thirteenth |
13 |

fourteenth |
14 |

fifteenth |
15 |

sixteenth |
16 |

seventeenth |
17 |

eighteenth |
18 |

nineteenth |
19 |

twentieth |
20 |

### Exceptions in Spelling

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

- twel
ve + th → twelf th - twent
y + th → twentie th

## 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 |
21 |

twenty-second |
22 |

twenty-third |
23 |

twenty-fourth |
24 |

twenty-fifth |
25 |

twenty-sixth |
26 |

twenty-seventh |
27 |

twenty-eighth |
28 |

twenty-ninth |
29 |

## 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 |
10 |

twentieth |
20 |

thirtieth |
30 |

fortieth |
40 |

fiftieth |
50 |

sixtieth |
60 |

seventieth |
70 |

eightieth |
80 |

ninetieth |
90 |

## 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:

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

The

Newton's

## 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:

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

## 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

The

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.