College Mathematics - BEDMAS vs. PEMDAS??

[jsd]

" 4 / 2 * 2. Your answer is either 4 or 1 depending on what you do first." 2*1/2*4 = 4 // division by 2 is multiplication by 1/2. // Order is irrelevant.

If you did multiplication first you'd get 4 / 4 = one. You don't do multiplication first, because divion came first in the problem.

"10-3+2, the correct answer is 9, not 5." // -3+2+10 = 9 // How would you ever get 5?

Same concept, if you did addition fist (just because "A" comes first in "PEMDAS") you'd get 10 - 5 = 5

[Old Guy]

If you did multiplication first you'd get 4 / 4 = one. You don't do multiplication first, because divion came first in the problem.



Same concept, if you did addition fist (just because "A" comes first in "PEMDAS") you'd get 10 - 5 = 5

Not to be blunt but you have never used a desk calculator. If you had the addition/subtraction question would be obvious. -3+2 never equals -5

Multiplication and division are the same thing. To divide by 2 you multiply by 1/2.

[jsd]

You're saying I can't use a calculator because I'm pointing out that 10-3+2 should NOT be done as 10 - (3+2), which using PEMDAS (or other acronyms) might mislead people into believing?

Okay man.

[Old Guy]

I get where you're coming from but why wouldn't you do like functions such as addition and subtraction simultaneously? With a desk calculator you put in the number and then you add or subtract it. There is no hierarchy. Addition and subtraction are identical.

[jsd]

I mean, that's the point. I'm giving the example of a WRONG way of doing it, which is a common mis-reading of PEMDAS. You should specifically not do it the wrong way I explained above. It's a fault of the acronym if you're not aware, and a fault of not doing like functions simultaneously.

This is like me saying "The word is spelled enough, don't spell it enuff"

And you saying I've never used a dictionary if I would ever think someone would spell it enuff.

[Old Guy]

I guess my point is why make a distinction? In my mind I don't ever subtract. I add negative numbers so there is never any reason to do it wrong.

[jsd]

We could be like LinkedIn and have a pointless discussion about what the answer must be.

Hey, you called it!

We all agree on the right answer but somehow there's still a weird dispute.

[jsd]

I guess my point is why make a distinction? In my mind I don't ever subtract. I add negative numbers so there is never any reason to do it wrong.

Congrats on doing it right?

Many people don't. Even that addition/subtraction example I used was not my own. It was from wikipedia, as an example of an overly simple problem that is commonly done wrong because of a PEMDAS misinterpretation.

Again, I'm saying "don't do it the wrong way," and you're saying "why not just do it the right way?"

[Old Guy]

Okay, we agree. The acronym makes no sense.

[jessikalauren]

I *think* I gathered what I need from this discussion - thanks everyone!

The first few questions I clicked through seemed to really reverse the orders in ways I wasn't accustomed to but I think I'll be fine.

Appreciate the help