Poll: 6÷2(1+2)

6/2(1+2) = ?

  • 9

    Votes: 516 68.9%

  • 1

    Votes: 233 31.1%
  • Total voters
    749
gambitt said:
No, there is nothing "usual" about it. Not once during my degree did I ever see anything written as ambiguously as 1/2x or 1/2(x). It would ALWAYS been written as a fraction.

Both are valid, the only thing "wrong" is the question.
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Well that because it won't arise in mathematics - unfortunately lots of programming languages/calculators etc.. require you to enter equations using an operator to represent division and that is what we're talking about - an expression on one line using '/' to represent division.

People have considered how to use '/' to represent division - there is a usual way to consider it and it isn't ambiguous.

6/2(1+2) is the same as (6/2)(1+2) and not generally to be read as 6/(2(1+2))
 
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gambitt said:
No, there is nothing "usual" about it. Not once during my degree did I ever see anything written as ambiguously as 1/2x or 1/2(x). It would ALWAYS been written as a fraction.

Both are valid, the only thing "wrong" is the question.
Click to expand...

I agree with you, but http://en.wikipedia.org/wiki/Order_of_operations

I figure if everyone takes a moment to spam this as often as possible, eventually the thread will just spawn the correct answer. So far only Hatter's been rabid & persistent in repeatedly posting the same link over and over again - he needs help.

We can get a definite answer to this, we just have t be stubborn enough.

http://en.wikipedia.org/wiki/Order_of_operations
 
shroomz said:
No I haven't. / is the divide symbol. I have typed the question exactly as I was given it.
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You have assumed that everything past the / should be divided, but some would argue that there are three separate terms and so you should only divide the second term as the third term is a separate operation.
 
gambitt said:
No, there is nothing "usual" about it. Not once during my degree did I ever see anything written as ambiguously as 1/2x or 1/2(x). It would ALWAYS been written as a fraction.

Both are valid, the only thing "wrong" is the question.
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Absolutely.

I'd imagine in computer science though, you'd see things like 1/2x fairly regularly though and would have a rule to deal with it. I think that's why certain people are getting very cross :D
 
No one should get 1 from that... Even if you think the sum is worded badly common sense should prevail.
 
LoL @ wiki:

wikitruth.png
 
Strife212 said:
It's meant to be
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But that is not what the question says. If you type the question into MathCAD, you get 1. If you add a space after the 2, taking the bracket term outside the denominator, then you get 9. There is no space, as such, MathCAD treats the 2(1+2) in the same way as for example 6/2a, rather than 6a/2. The question is ambiguous, and both answers are correct depending on whether you see the brackets being a coefficient of the denominator, or separate and thus part of the numerator.
 
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sk82jack said:
You have assumed that everything past the / should be divided, but some would argue that there are three separate terms and so you should only divide the second term as the third term is a separate operation.
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Exactly, and I believe it to be equally valid an assumption as the other.
 
shroomz said:
But that is not what the question says. If you type the question into MathCAD, you get 1. If you add a space after the 2, taking the bracket term outside the denominator, then you get 9. There is no space, as such, MathCAD treats the 2(1+2) in the same way as for example 6/2a, rather than 6a/2.
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That is because MathCAD, in that example, doesn't apply the standard order of operations. It requires you to be explicit.

Just because a calculator doesn't apply the standard order does not mean the question is ambiguous, unless you're going to call every question ambiguous where someone/something is wrong as opposed to right.
 
Tokenbrit said:
It has nothing to do with computer science either. You can replace 6,3,2 by x,y,z from any group with multiplication defined and it is the same.
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So you're saying if we let:

x=6
y=2
z=1+2=3

Then we write our equation as x/yz

The answer is still 9? ;)

The notation is poor. I don't know a thing about programming but I do know a thing or two about maths and I can tell you that the notation is rubbish. Whoever wrote this might get away with it in a computer program but not everyone will understand it - which means they've written it poorly. It is not clear enough whether we should be multiplying by 3 or its reciprocal.

Now, if your programming language of choice happens to understand what you've written correctly, then so be it (which was what I meant by my post, I wasn't making fun of computer scientists :p), but from a mathematician's point of view, the problem is poorly written, and if you wrote that down on a piece of paper I'd ask you to write it again.
 
dowie said:
Well that because it won't arise in mathematics - unfortunately lots of programming languages/calculators etc.. require you to enter equations using an operator to represent division and that is what we're talking about - an expression on one line using '/' to represent division.
Click to expand...

Blue160 said:
I'd imagine in computer science though, you'd see things like 1/2x fairly regularly though and would have a rule to deal with it. I think that's why certain people are getting very cross :D
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I thought comp sci guys had to have a decent A level in maths to do a degree. So we all agree that this 'problem' would only present itself as a result of user error?
 
Killerkebab said:
The notation is poor. I don't know a thing about programming but I do know a thing or two about maths and I can tell you that the notation is rubbish. Whoever wrote this might get away with it in a computer program but not everyone will understand it - which means they've written it poorly. It is not clear enough whether we should be multiplying by 3 or its reciprocal.
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You are right - the notation is rubbish, but apply the universally accepted standard order of notations and you get the same, right answer - 9.

terms inside parenthesis
exponents and roots
multiplication and division
addition and subtraction

Parsed left to right.
 
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