# The number or numbers of A and B

#### ryanlinlan

##### New Member
I am always confused with the singular or plural forms of "number" when I want to describe more than two things.

For example,
(1a) "The number of A and B in the set X exactly matches the number of A and B in the set Y, respectively."
(1b) "The numbers of A and B in the set X exactly matches the numbers of A and B in the set Y, respectively."

(2a) The set X contains different number of A and B from the set Y.
(2b) The set X contains different numbers of A and B from the set Y.

What I want to compare is that the number of A in the set X and Y, and the number of B in the set X and Y. Should I use "number" or "numbers"?

I hope my description is clear, and any suggestions are welcome.

Lin

• #### Chez

##### Senior Member
We would say 'the number of As and Bs in the set X...'

This sentence works OK. In effect we make 'plurals' of A and B. This can become awkward in some sentences, though.

#### Edinburgher

##### Senior Member
Yes, definitely pluralize the As and Bs. The question is whether also to pluralize "number". There is no case for this when there are only As and no Bs, but when there are both, and their respective numbers are different (for example if there are five As and seven Bs in each set), then there is. But the pluralization of "number", if done, would be additional to that of A and B.

Once we've turned every A and B in the OP's four example sentences into As and Bs, a few minor corrections are still required. In sentence 1b, the plural subject "numbers" requires the plural verb "match" (not "matches"), and in 2a the singular "number" requires the indefinite article "a" before "different": The set X contains a different number of As and Bs from the set Y.

#### ryanlinlan

##### New Member

(1a) "The number of As and Bs in the set X exactly matches the number of As and Bs in the set Y, respectively."
(1b) "The numbers of As and Bs in the set X exactly match the numbers of As and Bs in the set Y, respectively."

(2a) The set X contains a different number of As and Bs from the set Y.
(2b) The set X contains different numbers of As and Bs from the set Y.

Do you mean the above four sentences are all ok, Edinburgher?

#### ryanlinlan

##### New Member
According to the advice from PaulQ, the sentences should be rewritten as follows:

(1) The respective numbers of As and Bs in set X exactly match those in set Y.
(2) Set X does not have the same number of As or Bs as set Y.

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#### Edinburgher

##### Senior Member
Do you mean the above four sentences are all ok, Edinburgher?
Yes, they are ok, in the sense that there is nothing actually wrong with them.
They do sound a little long-winded though, and we would probably say something simpler:
(1c) Sets X and Y have the same number of As and Bs in them.
(2c) Sets X and Y do not have the same number of As and Bs in them.

#### ryanlinlan

##### New Member
Thanks for your further suggestions, Edinburgher!

#### The pianist

##### Senior Member
All of this could have been avoided if you had said:

"The cardinal numbers of A and B in the set X exactly match the cardinal numbers of A and B in the set Y."

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