Cardinal Numbers | Meaning & Examples
A cardinal number is a whole number (e.g., “three”) rather than a fraction (e.g., “one third”) or an ordinal number (e.g., “third”). In writing, cardinal numbers are determiners that show the quantities of nouns (e.g., “three cups of coffee”).
Cardinal numbers can go right before the nouns they modify or before other modifiers (e.g., adverbs and adjectives). When a noun has multiple determiners—such as the definite article “the” or the possessive adjective “my”—they always go before a cardinal number.
Depending on the style guidelines you’re using, you can write cardinal numbers as words (e.g., “seven”) or numerals (e.g., “11”). Some style guides recommend words for the cardinal numbers one through nine and numerals for 10 and greater.
My three black cats all have different personalities.
The manager hired four highly qualified software engineers.
I baked the two cakes on the counter for the party.
Cardinal and ordinal numbers
Cardinal and ordinal numbers are both determiners, but they have different meanings and spellings. You can use a cardinal number for counting or to express “how many” (e.g., “Tim earned two undergraduate degrees”).
An ordinal number shows the order or ranking of a noun in a sequence (e.g., “Tim’s first degree is in physics” or “The baby’s height is in the 90th percentile”). It can also be an adverb that shows the timing of a verb in a series of steps (e.g., “We watched the 1984 version of Dune first and the current version second“).
Whereas cardinal numbers can be written as words or numerals, ordinal numbers can be words or numerals combined with “-st,” “-nd,” “-rd,” or “-th” (e.g., “20th”).
Cardinal numbers | Ordinal numbers | ||
---|---|---|---|
Numerals | Words | Numerals | Words |
1 | one | 1st | first |
2 | two | 2nd | second |
3 | three | 3rd | third |
4 | four | 4th | fourth |
5 | five | 5th | fifth |
6 | six | 6th | sixth |
7 | seven | 7th | seventh |
8 | eight | 8th | eighth |
9 | nine | 9th | ninth |
10 | tenth | 10th | tenth |
Sometimes the numeral versions of ordinal numbers have the letters in superscript (e.g., “Grandpa’s 100th birthday”). When you’re writing ordinal numbers as numerals, check with your school or workplace formatting requirements.
Cardinal numbers | Ordinal numbers |
---|---|
The temperature in Nova Scotia is usually around 9°C in March. | Perez scored a homerun at the beginning of the ninth inning. |
Twenty-seven guests requested vegetarian entrées. | Most of the students at Stanford have SAT scores in the 75th percentile. |
When to spell out numbers
Each workplace, academic department, or publication usually has guidelines about when to spell out numbers. The most common guidelines are as follows:
- Spell out one through nine, and use numerals for 10 or greater.
- When cardinal numbers 10 or greater begin a sentence, use words instead of numerals (e.g., “Forty people applied for the sales position”).
- Use a hyphen in numbers that have two words (e.g., “thirty-six”).
When you’re writing essays, dissertations, or other school assignments, the rules about how to write cardinal numbers depend on whether you’re using APA, MLA, or Chicago style.
APA
APA generally requires words for single digits and numerals for 10 and above (except at the beginning of a sentence). However, APA also uses numerals for single-digit numbers in certain situations.
APA guideline | Example |
---|---|
Words for one through nine (with the exceptions explained below) | Sam has two part-time jobs and lives with three roommates. |
Numerals for 10 and greater | After 15 years of service, Dwight finally got a promotion. |
Numerals for all numbers that show percentages (written as “%”), ratios, ages, sums of money, measurements, times, and dates | The patient is 9 years old and takes 5 mg of loratadine per day during allergy season. |
Numerals after nouns that refer to a numbered series, which are always capitalized (e.g., “Grade 9”) | None of the students answered Question 2 correctly. |
MLA
In MLA writing, words are more common than numerals for cardinal numbers. MLA only uses numerals for numbers that have three or more words and in a few other situations (e.g., MLA dates). MLA doesn’t hyphenate two-word numbers.
MLA guideline | Example |
---|---|
Words for all numbers that are one or two words (even percentages) | The average starting salary for US teachers is less than fifty thousand dollars per year. |
Numerals for numbers that have three or more words | Patrick has played in 130 NFL games. |
Numerals for measurements, times, and dates | The ideal weight for a pug is 14 to 18 pounds. |
Combination of numbers and words for multiples of a million, billion, or trillion that are more than two words. | The population of New York is approximately 19 million. |
Chicago
In Chicago style writing, numbers from zero through 100 are always spelled out (with hyphens in two-word numbers). Chicago requires numerals for 101 and greater as well as for units of measurement and percentages.
Chicago style guideline | Example |
---|---|
Words for zero through 100 | Charlie invited twenty-two guests to the party. |
Numerals for 101 and greater | The maximum capacity of this music venue is 500. |
Numerals for measurements, times, dates, and percentages (with “percent” spelled out instead of “%”) | Only 64 percent of eligible voters participated in the election. |
Numerals after nouns that refer to a numbered series and no capitalization for those nouns (e.g., “level 5”) | The standardized test is for students in grade 5. |
Frequently asked questions about cardinal numbers
- Do you spell out numbers under 10?
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In most cases, spell out numbers under 10, which include cardinal numbers (e.g., “four books” and “nine teachers”) and ordinal numbers (e.g., fifth grade). However, there are exceptions and variations, depending on the style guidelines you’re using.
For example, APA, MLA, and Chicago guidelines require numerals for numbers under 10 when they’re part of dates, times, and measurements (e.g., “The veterinarian fed the kittens a high calorie diet until they weighed 2 pounds”).
You can also use numerals for one through nine when they go after nouns and are part of a series (e.g., “Chapter 7 takes place in a cave”).
Always check with your style book, instructor, or workplace guidelines when you’re unsure about how to spell out cardinal numbers or ordinal numbers.
QuillBot’s free Grammar Checker can also help you use numbers correctly in your writing.
- Do you hyphenate numbers?
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Most (but not all) style books say to hyphenate numbers that have two words (e.g., “forty-six days”).
Unless your style requirements say otherwise, use a hyphen (-) when you need to write the words for a double-digit cardinal number (e.g., “thirty-one flavors”) or ordinal number (e.g., “twenty-first birthday”).
Some of the most common guidelines for hyphens and numbers are as follows:
- APA uses hyphens for two-word numbers but only uses words for 10 and greater at the beginning of a sentence (e.g., “Last year, 25 teachers retired” or “Twenty-five teachers retired last year”).
- Chicago uses words for numbers up to 100 and hyphens in numbers with two words (e.g., “The conference included workshops by twenty-seven professional musicians”).
- MLA requires words for all numbers that have one or two words and doesn’t use hyphens for numbers (e.g., “The researchers interviewed thirty two students”).
QuillBot’s free Grammar Checker can help you with hyphens, cardinal numbers, and more.
- Are numbers adjectives?
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Cardinal numbers (“one,” “two,” “three,” etc.) can be placed before a noun to give information about quantity, and ordinal numbers (“first,” “second,” “third,” etc.) can be placed before a noun to give information about order.
While these numbers look like adjectives, they are in fact quantifiers, which is a type of determiner.