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Are Numbers Adjectives?

Numbers give us information about things and allow us to count, label, and measure items in our world, but because there are so many ways that we use numbers, they are not always that easy to categorize. For instance, are numbers adjectives?

Numbers are not adjectives, they are “determiners” or “quantifiers” when they appear before nouns. Numbers are versatile and can also be nouns, pronouns, or, occasionally, even adverbs, depending on where they stand in a sentence and how they are used. The few grammarians who consider numbers to be adjectives refer to them specifically as numeral adjectives.

This article will explore the broad role of adjectives, examine determiners and quantifiers, and consider numbers as adjectives. We’ll also look at the use of numbers in other contexts and note what parts of speech they are.

What Is an Adjective?

Adjectives are words that give us additional information about something by describing a noun or a pronoun. According to traditional grammarians, adjectives are one of the eight parts of speech in the English language. 

The other seven are nouns, pronouns, verbs, adverbs, prepositions, conjunctions, and interjections. The primary function of an adjective is to modify a noun or pronoun and make it more interesting and specific. 

Sometimes, we use a group of words to modify a noun or pronoun, and this is then an adjective clause if it has a subject and verb or an adjective phrase if it doesn’t have a subject and verb (source).

Below are some examples of adjectives and adjectival clauses and phrases:

Adjective: Jack chose the blue toy.

Adjective phrase: Sheila is taller than you. 

Adjective clause: My brother, who is younger than me, is a doctor. 

We can generally use adjectives in two positions. We call those that precede the noun or pronoun “attributive adjectives,” and we call those placed after a verb “predicative adjectives.” Below are some examples of both.

Attributive adjectives

  • The pretty girl was on the bus.
  • The huge elephant walked past us.
  • The cold weather kept them indoors.

Predicative adjectives

  • The girl on the bus is pretty.
  • The elephant seemed huge.
  • The weather felt cold.

One of the roles of adjectives is to compare and contrast the nouns they describe. Comparative adjectives compare two things, while superlative adjectives contrast three or more things, as shown in the examples below.

Comparative adjectives

  • Jane is taller than Mary.
  • Your lipstick is brighter than mine.
  • His dog is smaller than hers.

Superlative adjectives

  • That is the highest building in our town.
  • Jane is the tallest girl in the grade.
  • His dog is the smallest I’ve ever seen.

Consider the sentence, “There were five naughty boys.” Traditional grammarians would classify both “five” and “naughty” as adjectives. However, the sentence doesn’t make sense without the “five” or something similar in its place, so we need to look a little closer at numbers and their role.

What Is a Determiner?

In traditional English grammar, determiners are often classed as adjectives, and many determiners can play the role of both.

As we explore determiners, you will notice a significant overlap between the two categories. Modern linguists, however, class them as the ninth part of speech.

Like adjectives, determiners give further information about a noun or pronoun. However, where adjectives modify a noun or noun phrase, determiners provide a reference to something that is already in context.

Determiners usually don’t have comparative or superlative forms — big, bigger, biggest — and generally precede adjectives if they occur in the same phrase. A noun can usually only have one determiner, while there can be many adjectives.

If adjectives are eliminated from a sentence, the sentence just becomes less interesting, but it is still a sentence. Determiners are more integral and cannot simply be removed (source). There are five common types of determiners, as outlined below.

Articles

The three articles used in English are “the,” “an,” and “a.” “The” is a definite article because it refers to a specific noun, and “a” and “an” are classified as indefinite articles because they refer to a class of nouns. 

Serena Williams is an athlete.

The Statue of Liberty is iconic.

I would like a drink.

Determiners of Number or Quantity 

As expected, these describe the number or quantity of something and answer the questions “how much?” or “how many?” They are also sometimes called “quantifiers.”

We don’t have much time before our meeting.

There were too few children to make a team.

Please show a little kindness to him.

There were five ducks in the pond.

Demonstrative Determiners

These indicate specific people or things and always precede the noun or pronoun they are modifying. The most common demonstrative determiners are “this,” “that,” “these,” and “those.” Below are some examples using them in a sentence.

Gramma always buys this brand of jelly.

I was embarrassed when I tripped over those boxes.

I’d like to try that candy.

Possessive Determiners

Possessive determiners demonstrate possession or ownership. They also always come before the noun in a sentence, as shown below.

Corey lost his jacket.

Jane loves her phone.

I did all my homework before practice.

Interrogative Determiners

These determiners ask questions and are always followed by a noun in a sentence. The three interrogative adjectives are “what,” “which,” and “whose,” and their use is shown in the examples that follow.

What book are you reading?

Whose jacket is this?

Which color do you prefer?

Board, Questions, Who, What, How, Why, Where
Image by Gerd Altmann via Pixabay

Are Numbers Adjectives or Determiners?

In most uses, numbers are determiners of quantity or quantifiers. This would make them a type of adjective if you accept that determiners fall under this category.

If you believe, along with most modern grammarians, that determiners should stand alone, then they are not adjectives.

Those that accept numbers as adjectives refer to them as numeral adjectives (source).

Cardinal and Ordinal Numbers

Numbers can be cardinal as in one, two, three, etc., or ordinal as in first, second, third, etc.

Cardinal and ordinal numbers are mostly used as determiners. Like other determiners, numbers come before the noun or noun phrase, and they also precede any adjective (source).

When using cardinal numbers as determiners, we can combine them with articles or possessive determiners. Below are some examples of cardinal numbers as determiners. 

These are my five best friends.

Where are the two books you mentioned?

I have a hundred questions for you.

Ordinal numbers are used to place things in order and are also commonly preceded by articles or possessive determiners. Below are some examples of ordinal numbers as determiners.

This is the third driving test he has failed.

Where will you be on May 1st?

She celebrated her 13th birthday in Hawaii. 

In addition to the most common categories of cardinal and ordinal, numbers can also be multiplicative (once, twice), multipliers (double, triple), or distributive (singly, doubly). 

Numbers as Nouns

Most of the time, numbers act as determiners, but there are occasions where both ordinal and cardinal numbers can be used as nouns. Consider the examples below.

I liked all the contestants, but I’m voting for the fourth.

The animals entered the arc in twos.

One is the smallest number. 

Numbers can also commonly be part of a noun such as in the following examples:

  • Highway 4
  • Grade 7
  • Channel 2
  • Flight 627

Numbers as Adverbs

Numbers can be used as adverbs, and these are referred to as adverbial numbers. They talk about how often an action takes place, thereby modifying the verb. Below are some examples of numbers used in this context.

You need to ask first.

I’ve called his number twice.

He came tenth in the race.

Numbers as Pronouns

There is some debate about whether all numbers can be used as pronouns. However, there is consensus that “one” is definitely a pronoun in the context where it refers to people in general, such as in the following examples.

One never knows what to expect.

Holidays should allow one to relax.

Read more about this tricky pronoun here in our article, “’A One’ or ‘An One’?” More contentiously, some grammarians would class the following uses of numbers as pronouns while others would disagree.

The two went to the shops.

The other four went to fetch help.

Do you agree? As you can see, English grammar is never without its exceptions.

Image by SevenStorm via Pexels

Dates, Measurements, and Time

We use numbers to indicate dates, measurements, and time. There are many ways of writing these, depending on where the writer is located. The numbers used in this context are nouns. 

In the US, dates are generally written in the order of month, day, and then the year. So, one would say, “That happened on August 4th, 2010.” 

Most non-US countries will specify dates as day, month, and then the year and would say, “That happened on 4 August, 2010.”

Time is measured either in a 12-hour or 24-hour clock. The 12-hour clock divides the day into two sections — the hours from midnight to noon and the hours from noon to midnight. 

The 24-hour clock, where the day runs from midnight to midnight, is most commonly used around the world. However, in the US, the 12-hour clock is used more widely, and the 24-hour clock is referred to as military time. 

Numbers are also used to determine units of measurement. A variant of the imperial system is used in the US, and this includes units such as feet, inches, miles, and pounds.

Globally, most countries use the metric system, which uses units such as meters, kilograms, and kilometers.

Rules for Writing Numbers

Numbers often have to be written, and various rules govern how to do so correctly.

It’s best to spell numbers out if they occur at the beginning of a sentence. It is also generally accepted that you should spell out numbers one through nine, and use numerals from 10 upwards, as seen below (source).

There were five children in the class.

There were 19 children in the class. 

The exception for this would be when comparing numbers that fit in both categories, such as the example below:

Infection was observed in 4 of the 18 cases.

The 4th and 12th grades are considered the most challenging.

Here, even the numbers one through nine are written using numerals for consistency.

We should use commas to separate units of a thousand, as shown in the numbers below:

  • 1,425 miles
  • 66,789 people
  • 2,903,675 citizens

Numerals should be used before any unit of measurement, date, or time and the unit itself should be abbreviated, if possible, as shown below:

  • 6 days
  • 7 miles
  • 35℉
  • March 9
  • 2%

Numerals should be used for all math functions, but common fractions can be spelled out, as shown in the sentences below:

  • Use a ratio of 12:1 to mix the oil and water.
  • Her result in the science test was 86%.
  • A quarter of the patients received placebo medication. 

Numerals are generally used to indicate age, as in the examples below:

  • The 15-month-old has just learned to walk.
  • Women in the 60s are susceptible to that disease.

When detailing a range of numbers, write them in full if they are below 100 and give at least the last 2 digits if they are larger than 100. If the numbers refer to years, then give as many as required for clarity.

  • 7 – 8 months
  • 121 – 25 people
  • 1920 – 2001

Decades are written in numerals without an apostrophe — the 1980s, 2000s, etc. 

Final Thoughts

Not everyone accepts numbers as adjectives but, when they do, they refer to them as numeral adjectives. Numbers can certainly play the role of adjectives, but they can be used in so many different ways too. 

For most purposes, numbers are determiners of quantity and can be relatively easily classified. However, we’ve shown examples of numbers used as nouns, pronouns, and adverbs, which just goes to show how flexible digits in the English language really are!