I was taught BEDMAS in school, so slightly different order. I was also taught that DM and AS are not specifically in that order, but rather left to right of the equation, in the same lesson. I’m not sure why some schools aren’t doing it that way.
Comment on SBA #119 maths
cattywampas@lemmy.world 3 weeks ago
It’s 9 if you actually understand PEMDAS
BurntWits@sh.itjust.works 3 weeks ago
Reyali@lemmy.world 3 weeks ago
I’m guessing confusion is coming from those taking PEMDAS literally as that order? Rather than PE(M|D)(A|S), like it’s supposed to be?
cattywampas@lemmy.world 3 weeks ago
It’s also convoluted by the notation of the multiplication. When it’s written like this, many assume that you need to resolve that term first since it involves parentheses.
Jarix@lemmy.world 2 weeks ago
This is how I was taught 30 years ago in highschool
FishFace@piefed.social 3 weeks ago
It’s also because writing multiplication without a symbol creates a tightly bound visual unit that is typically evaluated before other things. If you see an exercise like, “what is 4x²/2x” most people answer “2x” not “2x³”. But this convention is rarely taught explicitly, so it’s ripe for engagement bait.
0ops@piefed.zip 3 weeks ago
I think you nailed it on the head. The expression isn’t technically ambiguous, there’s exactly one solution, and neither is the notation incorrect, just unconventional. In this case though, forgoing convention makes the expression typographically misleading. Hence a reason why we have these conventions for writing out expressions in the first place: to visually reinforce the order of operations thereby making expressions as easy to read as possible. So it’s not written wrong per se, just unnecessarily confusingly.
marcos@lemmy.world 3 weeks ago
There’s a reason why the conventional division symbol requires grouping its terms.
If you see an exercise like that, the exercise is bad and your teacher must be educated.
FishFace@piefed.social 3 weeks ago
I’m talking about exercises in textbooks, and you can find enough examples that writing them off as “the exercise is bad” is not really a good enough response.
The only way the exercise is bad is if it causes confusion in the people who are using the textbook. Those students have been exposed to the conventions of the textbook in question; they’re not people who were brought up on some other convention. You do see inline division and the vast majority of people interpret an expression like that above the way I said, so it’s not in practice confusing.
It’s not realistic to demand that every textbook uses the same conventions. It is realistic to demand that they lay out such conventions explicitly, which they unfortunately don’t.
purplemonkeymad@programming.dev 3 weeks ago
Well implicit multiplication would be done before the other operators anyway, but after exponents. Pemdas is incomplete.