Poll: 6÷2(1+2)

6/2(1+2) = ?

  • 9

    Votes: 516 68.9%

  • 1

    Votes: 233 31.1%
  • Total voters
    749
http://en.wikibooks.org/w/index.php?title=Algebra/Order_of_Operations&stable=0

The first line makes interesting reading.

screenshot1eft.png
 
Blue160 said:
Maybe true, but the post above yours shows how a mathematician might see the problem. Programmers are used to seeing problems written as one line, and have rules to deal with it. A mathematician immediately imagines what the problem would look like if it were written out properly.
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I'd be upset if a mathematician didn't know the standard order of operators, though.
 
This has probably been done already but what the hell. It's going to look pretty pedantic as well but bear with me...

Take a similar expression in exactly the same form:

1/2(a+b)

let x = a+b to simplify it:

1/2(x)

As I've said before it's equally valid to assume this is either:

1
---
2x

x
--
2

but at first glance I would read it as "1 over 2x" not "half of x".
 
Castiel said:
This is what I get:

6÷2(1+2)=9



6/2(1+2)=1


lol.
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Casio have presumably defined the divisor to be everything beyond the '/' - or at least with that model.

Looking at your screen print the divisor is made clear and in most other calculators you'd have to enter 6/(2(1+2))

The answer in that case is obviously 1 but this isn't conventional.

Anyway this isn't a maths problem but rather an illustration that some people have implemented '/' differently and that without parenthesis some people are confused by it.
 
vonhelmet said:
I think what we can conclude is that those with a rigid adherence to year 10 rules get 9, and those who have ever used maths for anything even remotely applied think the question is ambiguous.
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Says the Grammar Nazi. 1 is just wrong. The thing is, it's not in an applied context. We've just been given that as the question - and you get 9.


shroomz said:
2dqvhgy.jpg


I'll put my "low end" calculator away now ;)
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Erm you have totally changed the equation for a start.
 
As a mathematician I see it like this:

Define X= 6, Y= 2, Z= 1+2= 3


this gives

X / Y x Z


But dividing by Y is the same as multiplying by the reciprocal of Y, therefore

X x (1/Y) x Z

Which then substituting for X, Y and Z you get

6 x 0.5 x 3

= 9
 
dowie said:
Casio have presumably defined the divisor to be everything beyond the '/' - or at least with that model.

Looking at your screen print the divisor is made clear and in most other calculators you'd have to enter 6/(2(1+2))

The answer in that case is obviously 1 but this isn't conventional.

Anyway this isn't a maths problem but rather an illustration that some people have implemented '/' differently and that without parenthesis some people are confused by it.
Click to expand...

Yeah, I changed the way the calculate displays and the answer changes....see edit.
 
i would say it has to be 1
it would have to be (6/2)(1+2) for the answer to be 9 but with no brackets around the first term it implies that it is 6/(2(1+2))
 
dowie said:
Nah its usual for 1/2x to be read as (1/2)x and not as 1/(2x)
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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.
 
I would have probably gotten 1 when I was at secondary school doing GCSE Maths. (which was only last year >__>).

I'd rather not think about Maths anymore though, there are better things to do.
 
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