Is it correct to say “times” in this context?

Consider the following:

Math teacher: "How can we turn 42 into 420 through multiplication?"

Student: "You times it by ten!"

Is this usage of times correct? I hear it so often that I suspect it may be correct. I'm sure the reason for this (potential) mistake is that it is correct to say:

"Ten times four is forty."

Does anyone know if this is correct or not?

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Apparently "you pays your money and takes your choice". Some people will think you're stupid, childish, or ill-educated if you say/write times. Others won't, but they won't think you're pedantic or stuffy if you write multiplied by, so you might think that's safest. – FumbleFingers Oct 18 '11 at 23:26
I personally do not support the above usage of "times". I was just curious enough to find out if it was right or not. – user11550 Oct 18 '11 at 23:27
Ah. So you already know which horse you're backing! I'll remember not to use times as a verb when writing to you then! :) – FumbleFingers Oct 18 '11 at 23:29
@FumbleFingers Indeed! I would never use times in that context. It sounds awful when spoken and looks the same when written. – user11550 Oct 18 '11 at 23:30
It's possible SE England is more tolerant of the usage than Canadians. Or, of course, maybe I'm stupid, childish, and ill-educated! :) – FumbleFingers Oct 18 '11 at 23:32

In Standard English, this usage of the word times is considered an error. It is often used by children and students when speaking of multiplication, for exactly the reason that you indicate: the formula X times Y equals Z has spawned the creation of a verb to times meaning to multiply.

However, using this in any kind of formal context is considered an error, and I have only ever encountered this usage from children. I would avoid it in writing altogether, and discourage students from using it.

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That's where I hear it the most; among students and children. – user11550 Oct 18 '11 at 23:18
I think it's just one of those things you wouldn't say in a formal setting. Informally, it's said all the time, even by adults. – Sarhanis Oct 18 '11 at 23:19
Merriam-Webster get quite worked up about this "error". I don't see anything wrong with it in informal speech, though if I was writing I think I'd always use multiplied by (or more likely just "x"). But NGram has thousands of written instances of times it by, and most of them aren't MW's vitriol. – FumbleFingers Oct 18 '11 at 23:20

Most dictionaries will tell you times is a preposition, though it is closer to an interposition, which some might call a conjunction. It could be seen as a noun with "ten times four" meaning "four, ten times", or by parsing "Learn your three times table." Alternatively, twice is seen as an adverb.

Personally I would accept times as a verb if that is how somebody wanted to use it, for example if they said "Times the decimal fraction by 100 to get a percentage", though I would more often use multiply in that context.

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When I was a child in primary school, anyone using "times" as a verb would be corrected by the teacher. The modern fashion is not to correct children's mistakes as it stresses them, or lowers their self esteem. So what once were considered errors become common usage, and rabble-pandering "authorities" like OED eventuallt accept this misuse of language as correct. You multiply two numbers together: you do not "times" them

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Times comes from the idea of repetition!

Q. The pirate put five coins into the bag. If he did this ten times then how many coins would the bag contain?

A. The bag contains ten times five coins (fifty)

Mathematically, times belongs between two numbers (and belongs to the first one if you see what I mean)

Hearing "You times that number by that other number" makes me want to vomit!

Junior math(s) teachers will often say "times means multiply", but the two are not always interchangeable.

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The answer is YES! It is correct. Why say mul-ti-ply when you can say times? Why say mul-ti-pli-ca-tion when you can say timesing?

As a verb instead of multiplying:

1994, Harvey Mellar, Learning with artificial worlds: computer-based modelling in the curriculum:
I've taken the calories and the amount of food . . . and it's 410 calories per portion timesed by 6 portions which [sic] the answer was 2460 calories...

1995, Mathematical Association, The Australian mathematics teacher, Volumes 51-53:
A student as junior as Year 4 informed me that he made a forward estimate of cheeses in 100 trials by 'timesing both numbers by 10'...

1998, Psychology of mathematics education, Volume 2:
Alex: Yeah - if you're timesing that distance there by this height, it will disappear.

2011, Willis, et al, Willis's Elements of Quantity Surveying, 11th ed, p33, Wiley-Blackwell, West Sussex, UK:
Calculation should be made as waste on the dimension paper and not mentally, and timesing should be done consistently.
When timesing becomes complicated, it will help considerably in tracing items if the method of timesing is consistent.

There are many byspels ... Resist it if you like, but you're spitting into the wind.

Late edit: I only now realized that I forgot to mention that times as a verb (times, timesed, timesing) is in the OED.

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I think you meant 'by-games'. – Mitch Dec 28 '11 at 2:52
'correct' usually means in reality 'accepted by the standard'. Using 'times' as a verb might be used informally all over the place, but is definitely not standard and using it as a student in an assignment or in any communication with anything other than the most informal situations is a grave stylistic solecism. – Mitch Dec 28 '11 at 2:55
@AnWulf: 'byspel' is not a recognized word in modern English. – Mitch Dec 29 '11 at 3:10
@AnWulf: Your first three examples are all quotes of informal speech by students. For ESL students, if you use 'timesing' you will sound foreign or uneducated. – Mitch Dec 29 '11 at 3:13
@AnWulf If you did not insist on its "correctness", you might not be downvoted. OED is only recording the usage, as its lexicographers are more descriptivistic now. Still, people say whether a certain usage is correct or not. When most people say it is incorrect, it is, then. This can certainly change, and the once controversial usage of words like "hopefully" can be mainstream. This does not happen all the time, though. At least for now, I consider "times" ugly as a verb, and won't accept it. – Yongwei Wu May 27 '15 at 4:19