**Cardinal number definition: **A cardinal number is a number that expresses how many of a particular item exists.

**Ordinal number definition: **An ordinal number is a number that expresses a position relative to others.

## What is a Cardinal Number?

Cardinal numbers are simply numbers. Cardinal numbers tell us how much of a certain quantity there is.

**Examples of Cardinal Numbers:**

- 1
- 18
- 23
- 877
- 59

**Examples of Cardinal Numbers:**

- one
- eighteen
- twenty-three
- eight hundred seventy-seven
- fifty-nine

**Examples of Cardinal Numbers in Sentences:**

- I purchased one apple.
- They ordered 18 sandwiches.
- He wore the number 23.
- I think there are 877 jellybeans in the jar.
- My dad turns 59 this year.

## What is an Ordinal Number?

Ordinal numbers are numbers that tell a particular position or place.

**Examples of Cardinal Numbers:**

- 1st
- 3rd
- 7th
- 33rd
- 100th

**Examples of Ordinal Numbers:**

- first
- third
- seventh
- thirty-third
- one hundredth

**Examples of Ordinal Numbers in Sentences:**

- The pig placed first at the county fair.
- She celebrated her third birthday
- Sam is my seventh pet.
- Our school is thirty-third in the state.
- It is the one hundredth anniversary of our city’s founding.

## Spelling Numbers Out

The only cardinal numbers that should be written out—not abbreviated with a number—are the numbers one through nine. This is in accordance with AP Style, which is widely held by writers, news publications, journalists, etc.

All other cardinal numbers should be written numerically.

**Examples:**

- Correct: We have one dog.
- Incorrect: We have 1 dog.

- Correct: You need three pencils
- Incorrect: You need 3 pencils.

- Correct: Please buy 40 cups.
- Incorrect: Please buy forty cups.

- Correct: She had 11 items on her list.
- Incorrect: She had eleven items on her list.

All ordinal numbers should be spelled out in writing, not abbreviated.

- Correct: The team took second place.
- Incorrect: The team took 2nd place.

- Correct: They gave a medal to the fourth finisher.
- Incorrect: They gave a medal to the 4th finisher.

Of course there is nothing grammatical *wrong* with spelling out larger numbers or using figures for those under 10. These are simply the most conventions across all types of English.

## When Is It Okay to Use Figures?

Sometimes it is acceptable to use a figure (number) instead of writing out the word. Those exceptions are detailed below.

**Addresses**

A street address requires a number. Therefore, it is acceptable to use a figure instead of writing out the word.

**Examples:**

- 1234 Ash Street
- My grandmother lives at 77 Rocky Lane.
- Her address is 5688 Tree Trail.

**Ages**

It is acceptable to use a figure when writing an age.

**Examples**:

- I have an 8-year-old cousin.
- I don’t remember life as a one-year-old.

**Proper Names, Proper Nouns**

Proper names and proper nouns can use a figure instead of the fully written word.

**Examples:**

- Let’s take Highway 1.
- The fastest route to Washington is Interstate 5.
- 88 freeway

**Millions, Billions, Trillions **

Large numbers should be written in a particular format.

**Examples:**

- Correct: $5 million
- Incorrect: five million dollars

- Correct: The Smith family is worth $2.1 billion.
- Incorrect: The Smith family is worth two point one billion dollars.

- Correct: What do you think $1 trillion looks like?
- Incorrect: What do you think one trillion dollars looks like?

NOTE: Do not ever begin a sentence with a figure. If you must begin a sentence with a number, write out that number. Starting numbers with figures is unacceptable.

- 500 jobs were created as a result of the tax measure. (Incorrect)
- Five hundred jobs were created as a result of the tax measure. (Correct)

Figures, however, will occasionally begin a headline.

## Summary

**Define cardinal numbers: **cardinal numbers are* numbers denoting quantity*.

**Define ordinal numbers: **ordinal numbers are *numbers denoting an item’s place in a series*.

In summary,

**Cardinal numbers**are numbers that represent how many of something someone has.- These are numbers like one, two, three, and four.
**Ordinal numbers**are numbers that represent place or position.- These are numbers like first, second, third, and fourth.

Both ordinal and cardinal numbers follow particular writing rules.