6/2(1+2) = X

[TPRJones]

Yes. The correct answer following the strict interpretation we have been discussing would be 8 if you do the division before the multiplication (left to right precedence). Yet Wolfram Alpha chooses do it wrong. Why? Because it's a vague way to write it to begin with.

EDIT: Like this. Technically the same, yet still different answers.



Edited By TPRJones on 1333141955

[GORDON]

Well blow me down.

[TPRJones]

If you decide to take those links back to Fark, let me know what they say.

EDIT: Although, the fact that Wolfram Alpha chooses to do this weakens that argument slightly. They've clearly coded it with input mistakes in mind to begin with, not because it's a proper way to read it.



Edited By TPRJones on 1333142326

[GORDON]

Nooooooo. The thread structure on their forums is NOT conducive to making a point, having it challenged, and rebuttal. There's no point arguing a point there... which is why 99% of the time I just seagull troll, because it amuses me making hippies get upset.

I love saying things in January like, "We've got 9 inches of global warming on the ground." Yeah, I know it isn't any kind of argument, but it makes a lot of Greens exasperated because they think I am seriously mocking them...... I bored myself in the middle of that sentence. Sorry.



Edited By GORDON on 1333142409

[TPRJones]

Is there a "left to right precedence" in math?

If so, wouldn't that prove that 9 is the correct answer or does it get ignored in this equation, and why?

It just seems that without that rule, a starting point other than the far left, once you got done with the parentheses, would be arbitrary?

Yes. And 9 is indeed technically correct. The thing is, in a properly written equation you should be able to do the associative operations in any order you want and still get the same result. The original equation being discussed is poorly expressed, like the math equivalent of awkward grammar. At least, that's my stance on the matter. Some others would disagree.



Edited By TPRJones on 1333142971

[TPRJones]

Heh. I was just curious about what WA would do with the difference between implicit and explicit multiplication:

x/2x where x=4 results in 1/4

x/2*x where x=4 results in 8



Edited By TPRJones on 1333143896

[Cakedaddy]

Math fail. Parentheses come first, always.

Gordon over thought the problem by multiplying 2x1 then 2x2 to come up with (2+4). The only time you do that type of 'double multiplying' is if there are variables in there 2(a+b) = 2a+2b, so that you can continue to solve for one or more of them. Otherwise, you do the parenthesis first. 2(3)=6. Yes the answer is the same no matter which way you do it, but technically, you did break the order of operations.

You're wrong. The answer is the same because it's the same. "Order of operations" doesn't matter because multiplication is distributive over addition. And it's not called "double multiplying," is called "distribution."

It's not "math fail" to distribute over constants, it's just not usually very useful.

Except that you do whatever is inside the parenthesis first. Period. You add them, then move on. Applying distribution is incorrect. You do what's in the parenthesis first. Yes, I said that twice for emphasis.

And what this argument is coming down to is what is perceived as general practice. Do people generally see it one way over the other? In my opinion, that's not acceptable in math. If you write an ambiguous problem, then neither answer is correct because the problem is broken. And this leads to you stealing $237,000 from your company over night instead of $2.37 because someone/thing perceived it differently than you intended.

The equation is unanswerable as written.