Originally Posted by MoonlitSunshine

ahahahahahahaa... Man, that's a good one.

Ever heard of Heisenberg's Uncertainy Principle? That you cannot know both the location and velocity of an atomic particle at the same time? Or what about the "Schodinger's Cat" paradox, which states that the cat is both alive and dead at the same time? It can't be both, because maths is hard facts, not multiple answers, right?

Even moving away from physics and into pure maths, x = 5 mod 6. What's x? Well, it's 5. It's also 11, and 16, and 365. In fact, it's 6n + 5, but without any information about n, you can't get a more accurate answer.

That's what's going on here. This is EXACTLY like a function with multiple possible values. Take a quadratic equation, like x^2 + 2x -3 = 0. "x" is both 3 and -1, right? You can't get one specific answer until you are given more information, like x>0. With this lovely equation, 6/2*(1+2) is both 1 and 9 unless more information about the order in which the multiplication and division should be done is given. Once the extra parentheses are added, the answer would be clear.

If anyone responds to this post with "but but but we were taught in school that you do PEMDAS" or "We were taught in school that if you have multiplication and divison in the same equation you just work from left to right", I am just going to ignore you, or assume that you're just completely incapable of reading seeing as I've explained this 5 times before.

THERE IS NO STANDARD CONVENTION FOR THE ORDER OF EVALUATION OF OPERATIONS. THEY ARE MADE UP IN ORDER TO MAKE IT EASIER TO TEACH THE SUBJECT. It just so happens that most of you tend to have been taught one of two common methods. This thread is all the evidence anyone should need to prove this is the case. If you want more, there's currently a facebook poll with about 2 MILLION votes, and about 200k difference between the two.

If anyone wants to argue this, I'm happy to do so, so long as you have an argument other than "look at these links" or "this is what my maths teacher said". I taught maths for 6 months, and the amount of white lies I had to say in order to avoid topics that were confusing the students was slightly soul-destroying. If anyone wants to disagree with me on the principle that you feel that you are right and I am wrong just because, please go and study maths - specifically Group Theory and Real Analysis - for a few years, and then get back to me.

/end rant