use of numbers, the number, and a number

[manhhiep2509]

Hello.

I search in oxford dictionary and see that "number" can refer to a quantity of people or thing, a symbol, or group of people. The problem is that I cannot tell when "number" refers to one of these meanings.

And it seems to me that "quantity" has the same meaning as "a group of people or thing". Is it correct?

For example:

(1) "A large number of people have applied for the job" -- the dictionary give the example to illustrate the meaning "quantity", but I do not see the difference if I think of "a large number of people" as a group of people.

(2) The number of homeless people has increased dramatically. -- the dictionary give the example to illustrate the meaning "quantity", but to me "The number" seems to refer to a symbol. How a group of people could fall?

Please explain and give examples when we use "number" to refer one of the above meaning of "number".
-----

through question 70 in review verbal 2, I know that when used in comparison, "X's numbers" must go with "greater", not "more".

do "The number" and "A number" follow the rule?

------

Through the question 70, I also see that a contradiction.

X's numbers is now five times greater than the past.

but

He is five times as old as his grandson.

do "The number" and "A number" follow the rule, as "X's numbers" does?

Thank you.

[RonPurewal]

As for whether you're referring to (a) the quantity of people or (b) the people themselves, that's basically common sense.

E.g.

(1) "A large number of people have applied for the job"

A number can't apply for a job, so this sentence is clearly referring to the people themselves. No different from, say, 400 people have applied for the job.

(2) The number of homeless people has increased dramatically.

People don't "increase", so this sentence is clearly referring to a number. (E.g., the number of homeless people has increased from 10,000 to 11,000.)

GMAC takes care not to create questions predicated on the use of a/an/the, so you shouldn't have to worry about those. But you may want to note their use here, as that's consistent (i.e., the number of xxxx is an actual mathematical quantity, whereas a number of xxxxx is like "several xxxx" or "lots of xxxx").

[RonPurewal]

through question 70 in review verbal 2, I know that when used in comparison, "X's numbers" must go with "greater", not "more".

do "The number" and "A number" follow the rule?

------

Through the question 70, I also see that a contradiction.

X's numbers is now five times greater than the past.

but

He is five times as old as his grandson.

do "The number" and "A number" follow the rule, as "X's numbers" does?

Thank you.

X's numbers is actually a different construction. It means "the population of X".
This is basically an idiom, and is restricted to exactly that form (possessive + "numbers"). I.e., you could not use the numbers of X to refer to the same thing.

This is the kind of idiom that was prevalent on the old GMAT when ETS still wrote the questions (10+ years ago), but is no longer on the current GMAT.
If you saw this question in the verbal supplement, you can feel free to disregard this idiom. (All the problems in the verbal supplement are at least as old as the 10th edition OG, i.e., quite old. SC has mostly stayed the same since then, but there's no more testing of obscure idioms.)

[sinyuchen.828]

Hi Ron，
MANHATTAN SC refers to " Never select an answer choice containing the phrase THE NUMBERS OF" But some answer choices accept this phrase

can you give me a explanation on whether i can use the phrase "˜THE NUMBERS OF'

[RonPurewal]

Hi Ron，
MANHATTAN SC refers to " Never select an answer choice containing the phrase THE NUMBERS OF" But some answer choices accept this phrase

can you give me a explanation on whether i can use the phrase "˜THE NUMBERS OF'

Basically, it's the same as with any other noun. If you're talking about more than one, then use the plural. Here, that means that "numbers" is ok if you're actually talking about more than one number.

E.g.,
This chart lists the numbers of various crimes committed in the city last year.
--> There's a different number for each kind of crime, so singular "number" would make no sense here.