What are “A number of” and “The number of”?

"A number of" and "The number of" are two phrases that confuse many English learners. Although they both imply a meaning of many or several, the context determines whether to use "The number of" or "A number of". In this article, PREP will share all the easiest ways to understand and distinguish between using "The number of" and "A number of".

I. What is “A number of”?

What is "A number of"? "A number of" is an English phrase used to refer to an indefinite or unspecified amount, often a significant or large quantity of something. For example:

• A number of students attended the workshop.
• A number of books were missing from the library shelves. 
• A number of factors contribute to climate change, including deforestation and greenhouse gas emissions.

II. What is “The number of”?

What is "The number of"? "The number of" is also a common English phrase used to refer to a specific numeric amount or quantity of something. For example:

• The number of participants in the marathon was higher than expected
• The number of cars on the road during rush hour can cause heavy traffic congestion.
• The number of COVID-19 cases has been steadily decreasing due to vaccination efforts. 

Basically, both "A number of" and "The number of" convey the idea of a plural quantity or multiple instances of something. However, "A number of" refers to an indefinite or unspecified amount, while "The number of" emphasizes a particular numeric value or definite quantity.

III. The usage of “A number of” and “The number of”

Besides the definitions, you also need to grasp the proper usage of "A number of" and "The number of". Let's explore together with PREP the correct usages of "A number of" and "The number of" below!

IV. Some notes on “The number of” vs “A number of”

There are some important notes on the usage of "A number of" and "The number of" in English you should remember to use them accurately and effectively. Here are some tips for you:

• A number of:
• "A number of" is commonly used with countable nouns, followed by a verb in plural form. For example: "A number of students were absent from class."
• Do not use "a number" before an uncountable noun. For example:
  • A number of water is needed for our body. (Wrong )
  • A quantity of water is needed for our body. (Correct )
• The number of:
  • "The number of" is commonly used with countable nouns, followed by a verb in singular form. For example: "The number of participants has increased."
  • Do not use "the number" before an uncountable noun.
    • The number of rice is increasing. (Wrong )
    • The amount of rice is increasing.(Correct ) 
• More notes:
• "A number of" expresses an indefinite or significant quantity.
• "The number of" expresses a specific numeric value or definite amount.

V. “A number of” vs “The number of”

What are the similarities and differences between “A number of” and “The number of?”. Let's find out with PREP through the table below!

VI. Exercises on “A number of” and “The number of” with detailed answers

To fully grasp the proper usage of "A number of" vs "The number of" and distinguish between these phrases, it would be great practice to work through some sample exercises provided by PREP.

Exercise: Fill in the blanks with “A number of” and “The number of”:

• ________ students attended the workshop on environmental conservation.
• ________ available parking spaces in the downtown area have decreased recently.
• ________ fruits, including apples, oranges, and bananas, were on sale at the market.
• ________ books were left on the table after the event.
• ________ participants in the marathon exceeded 1000 this year.

Answer keys:

• A number of
• The number of
• A number of
• A number of
• The number of

In this article, PREP has provided a detailed explanation of the structure, usage, and distinction between "A number of" and "The number of". Hopefully, this information will help students firmly grasp the concepts and be able to smoothly apply both of these grammatical structures!