Poll: 6÷2(1+2)

6/2(1+2) = ?

  • 9

    Votes: 516 68.9%

  • 1

    Votes: 233 31.1%
  • Total voters
    749
Castiel said:
Right then, is it:

6/2(1+2)....6/2(3)......2x3=6.......6/6 = 1.


or

6/2(1+2)......6/2(3)......6/2=3.......3x3 = 9.


Is there anyone (BetaNumeric or other Math Phd) who can confirm which it is?


It is doing my head in....
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If I was writing out the equation as it is I would say 1 without even thinking about it.

Looking at it again though I would say both answers are acceptable. If you put that into c++, mathematica, maple, matlab or any calculator I'd guess you would get conflicting answers.

However I would say when writing a mathematical paper the convention seems to be that if you are writing equations on a line, like we have, then everything after the forward slash is considered to be the denominator, which would imply the answer is 1.
 
Castiel said:
Right then, is it:

6/2(1+2)....6/2(3)......2x3=6.......6/6 = 1.


or

6/2(1+2)......6/2(3)......6/2=3.......3x3 = 9.


Is there anyone (BetaNumeric or other Math Phd) who can confirm which it is?


It is doing my head in....
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As said above it can be both, and the confusion is intentional.

It's like printing a sentence with a homonym like: "I tripped over a skate by the frozen pond today" and asking whether this means you tripped over a metal skate or the fish of the same name. It can be interpreted both ways, is purposefully ambiguous, and is largely a trap for assumptious people to fight over being right in an area that is very much grey.
 
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Eric's collar said:
I won a maths trophy in primary school. I think it's safe to say I'm not an idiot:p
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On this subject you have been.

The division DOES account for the (1+2) as well, if anything, I already explained that in my working above.

You can argue it is too vague, or that it can only be 1, there is no side of maths, physics, engineering or otherwise that would conclusively say that that equals nine
 
Rossuk89 said:
I've been taught to always do brackets first, so that's (1+2) which is 3.

Then do 6 divided by 2 which equals 3.

Then you're left with 3 (3), which means you times 3 by the number in the brackets (which is 3) which gives you 9?

Or am I wrong haha.
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Not entirely wrong. You are right about always doing brackets first, however you misunderstood that in "6/2(3)", the "2(3)" is an implied "(2*(3))", i.e. you have to do the 2(3) before you divide
 
p4radox said:
There's no consensus: it's presented badly. But most people who use maths would instinctively get the answer 1 by evaluating 2(1+2) first.

(I don't have a phd so feel free to ignore me...)
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Is it 6 divided by 2(1+2) though or 6/2 multiplied by (2+1). That is what seems to be the issue.

I asked the wife (math genius) and she asked to look at it and said it is a daft internet thing and ignore it and go to sleep.....:D
 
The answer is 1.

2(1+2) is shorthand for 2+4 or (2x1)+(2x2) which means that the 2 is part of the equation in the brackets. Thus to fully calculate the part of the equation associated with the brackets you have to do:

1+2=3
Then 3x2=6

From the original equation you then get 6÷6=1

If the original equation was 6/2(1+2) then it could be interpreted that 6/2 is a fraction which is then multiplied by the result of the addition in the brackets ie:

6 x (1+2) = 3x(1+2) = 3x3 = 9
2

But this is not how the equation is written so the correct answer is 1.
 
Ksanti said:
Not entirely wrong. You are right about always doing brackets first, however you misunderstood that in "6/2(3)", the "2(3)" is an implied "(2*(3))", i.e. you have to do the 2(3) before you divide
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Ah right. So that would be 2(3) is 6, then divide by 6 which equals 1.

Been a very long time since I've done maths like this!
 
I'd say 1, and I've done a lot of maths in my time.

However, the question is ambiguously written, and it doesn't help that it's all on one line so there's no way of discerning what actually belongs where. The argument is basically whether the question is:

(6/2)*(1+2)

which gives 9

or

6
_____
2(1+2)

which gives 1.

Without seeing it written properly one way or another, it's impossible to tell really. The stupid thing is that one way or another the question assumes that people are comfortable with the idea that adjacent items in a sum are multiplied together, regardless of whether a multiplication sign is present or not, which I think plenty of people will have trouble with.

However, having solved more equations than I care to recall, if I personally were writing that one line, then I would get to 1.
 
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Strictly speaking it should be 9 in this instance because it is an ambiguous question and BODMAS rules, then from left to right. If there were a couple of spaces in there such as 6/ 2(1+2) then it would be 1.
 
vonhelmet said:
I'd say 1, and I've done a lot of maths in my time.

However, the question is ambiguously written, and it doesn't help that it's all on one line so there's no way of discerning what actually belongs where. The argument is basically whether the question is:

(6/2)*(1+2)

which gives 9

or

6
_____
2(1+2)

which gives 1.

Without seeing it written properly one way or another, it's impossible to tell really.

However, having solved more equations than I care to recall, if I personally were writing that one line, then I would get to 1.
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I think it comes to the fact that most people who have used a lot of maths instantly think that the divide sign is a denominator (because lets face it, no-one uses a divides sign post GCSE) and thus end up with one.

However, strictly speaking if you leave it as a divide sign then you could technically correctly construe the 2 'belonging' to the 6 using the 'left to right' bodmas rule and end up at 9.

Damn you divide sign!
 
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