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Thursday, October 12, 2017


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1. The profits of car sales doubled in the last two quarters.
2. There were twice as many children books sold in 2016 as in 2017.
Twice as many books were sold in 2016 compared to 2017
3. there were a twofold drop in the number of drop-out at X school over the period from 2000 to 2016
The number of drop-outs at X school dropped twofold over the period from 2000 to 2016

The number of students in a university course doubled between 2005 and 2010.

There were twice as many students in a university course in 2005 as in 2010

Twice as many students were in a university course in 2005 as compared to 2010

There was a twofold decrease in the number of students in a university course between 2005 and 2010.

The number of students in a university course decreased twofold between 2005 and 2010

the number of immigrates to New Zealand increase twofold between 2010 and 2017.

there are twice as many work opportunities on the market in 2017 as in 2012.

Thanks a lot for this useful lesson, Simon.
Can you write a lesson to help us as learners make clear the following things?

1. "The chart compares the numbers of students..."
- Should we use "numbers" or "number"?

2. "Numbers of students increased..."
- Why is "numbers" used? Should "the" be added prior to "numbers"? Can we use "the number of" in this case instead?(I saw many model essays in textbooks use this expression, but can't use it on my own).

3. Is it natural to use "quantity" as in "the quantity of students"?

It would be great if there will be an image for each of the cases above.

Thank you very much in advance, Simon.


1. Both are possible, but it depends completely on what comes next. As a general rule, 'number of' is correct and 'numbers of' is only rarely correct. This is because we are usually referring to a category which has one number at any point in time. However, it is possible for a category to have various numbers, but unlikely.

2. 'the number of students' is generally correct. I can probably imagine a situation where you could be able to say 'numbers of students increased' but it would be unlikely.

3. No, it's not natural. We would use 'quantity' more for uncountable things: eg: the quantity of rubbish

1. 'double' (verb)
The house price doubled between 2015 and 2016 in this city.
2. 'twice as...as/compared to', 'three times as...as/compared to'
There were twice as many apartments sold in 2016 as in 2015.
Twice as many apartments were sold in 2016 compared to 2016.
3. 'twofold', 'threefold' (adjective or adverb)
There was a two fold increase in house price between 2015 and 2016.
The house price increased twofold between 2015 and 2016.

There were twice as many students in a university course in 2005 as in 2010.

Hi Simon,

How do we use 'as in'? Is it like an 'and'?

Can you please cite more examples for that?
Thank you

Oh sorry my bad. I read the sentence twice and I think it did not mean 'as in'. Haha

@ sjm

Thank you for your reply.

1. Your input is not clear to me, unfortunately.

For instance, the chart contains some separate years, say, 2000, 2001, and 2003. For each year, there are two bars each representing the number of students coming from a particular country. For example, there are two countries, Japan and the U.S.
Is this sentence "The bar chart compares the numbers of students coming from Japan and the U.S. from 2000 to 2003." possible?

2. Your reply is not clear-cut, I'm afraid. Specific examples would be great here.

3. I saw "quantity of students" in CNN news articles. Please google it and you can see. But I still wonder if that is grammatically correct in proper English.

Still, I look forward to Simon's clear-cut instructions, perhaps soon in a lesson on this blog. I (actually We learners) would like to hear from you, Simon. :)

Many thanks.


1. The choice between 'the number of' and 'the numbers of' is not clear in English, and varies between English speaking countries. However, 'the number of' is by far the most common. If you google this you will find many differing opinions and unfortunately there is not one clear rule. What I can say is that it depends on a number of factors, especially what you write AFTER the expression and how you phrase it. Yes, if you have multiple categories and sub categories (such as the example you have given) then it is fine to use a plural. I wish there was a better answer here but there isn't.

2. I actually cannot think of a natural example where a native speaker would say 'numbers of students increased'. A plural WITHOUT 'the' usually describes the whole of that group, and this is not the case here (we are talking specifically about students). Also, when we talk about 'increases' and 'decreases' we consider each category to be one individual number moving over a period of time, so we would not use a plural.

3. You are confusing grammar and collocation. It is grammatically fine to say 'quantity of students' but it is not natural. When you google this phrase you don't get many examples compared to more natural words like 'number' or even 'amount' (which is used both with countable and uncountable nouns). The only time 'quantity of students' is really used is with a percentage, and the writer is looking at 'students' not as individuals but as one large group - almost treating 'students' as an uncountable noun. This use is what we would call in English a bit 'figurative' or 'poetic'. Just use 'the number of students' and you will always be correct.

@ sjm

1. I did a lot of research, but could not find an agreed answer on this. There are quite many different opinions, even by English native people.

2. ....

3. This is not really related to my question, but "amount" is only used with uncount nouns, I'm araid, sjm. Oxford dictionaries say so. Also, Simon did write a lesson on this, saying "amount of + an uncountable noun".


I am a native speaker, and I work for exams that are conducted worldwide, and I've been teaching and training English for many years. You can believe my advice.

Yes, I agree with you about 'amount' and you can see my website page about this issue:


Also notice how we use 'figure' and 'figures'.

Nevertheless it is actually quite common usage in English to use 'amount' with a countable noun, but I wouldn't advise it in a writing test.


Clicking on the underlined blue phrases at the bottom provides examples (including a few false positives).

Clicking on "search lots of books" shows that "student numbers who" is not found; whereas "the numbers of students who" does come up.

"the number of students" is about eight times more frequent than "the numbers of students".

This is my answers to follow the patterns which teacher Simon gave.

1. The number of US residents travelling abroad doubled over the time period of 10 years.
2.There were twice as many participants in the workshop this year as last year.
Three times as many engineers are allowed to immigrate to Europe in 2017 compared to 2016.
3. There was a threefold increase in demand for vintage clothes between 2010 and 2017.
The number of old clothes collected so as to help people in Hagiang increased threefold between 2015 and 2017.

The number of tourist doubled between 2005 and 2009 in the country.

There were twice as much infrastructure rose in 2009 as in 2005.
Three times as many designer were engaged in workshop in 2009 compared to 2005.

There was a twofold increase in the number of students study abroad between 2005 and 2009.
The number of students study abroad increased threefold between 2017 and 2018.


1) "The number of ..." Is it followed by a singular or plural noun?

2a) "were" is a verb; so is "rose". So which is the main verb here? Why are there two?

2b) "designers": should it be singular or plural?

3) "study": there are other forms of the verb like "studying", which can sometimes be used somewhat like an adjective. Try googling "reduced relative clause".

@ vonZoyten

Thank you for your reply.

The number of tourists doubled between 2005 and 2009 in the country.

a.)There were twice as many country's infrastructure rose in 2009 as in 2005.

b.)Three times as many designers were engaged in workshop in 2009 compared to 2005.

3.Is mean that my sentences aren't right?

Thank you.

@ Esther
2a) There was twice as much infrastructure in 2009 as in 2005.
OR There were twice as many rises in infrastructure..
OR There were twice as many countries with rises in infrastructure...

3 the number of students studying abroad


Thank you.

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