• barsoap@lemm.ee
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    4 days ago

    Why? Because a bunch of dead Greeks say so!

    The Greeks certainly didn’t come up with PEMDAS. US teachers too lazy to teach kids actual maths did. And that’s before taking into account that the Greeks didn’t come up with Algebra.

    • dohpaz42@lemmy.world
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      4 days ago

      US teachers too lazy to teach kids actual maths did.

      What’s lazy about learning PEMDAS? And what’s the non-lazy/superior way?

      • barsoap@lemm.ee
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        4 days ago

        Learning the actual algebraic laws, instead of an order of operations to mechanically replicate. PEMDAS might get you through a standardised test but does not convey any understanding, it’s like knowing that you need to press a button to call the elevator but not understand what elevators are for.

        Though “lazy teachers” might actually be a bit too charitable a take given the literacy rates of US college graduates mastering in English. US maths teachers very well might not understand basic maths themselves, thinking it’s all about a set of mechanical operations.

        • Halosheep@lemm.ee
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          4 days ago

          This guy is the the guy posting the answer and then spending hours fighting the idiots who got it wrong on Facebook.

          Nerd.

        • AbidanYre@lemmy.world
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          3 days ago

          Is it also lazy to learn Roy G. Biv to know the color spectrum instead of learning all the physics and optical properties behind that?

          Or what about My Very Elderly Mother Just Served Us Nine Pickles to know the planets instead of learning orbital dynamics and astrophysics?

          Christ man, it’s a mnemonic device for elementary schoolers.

          • barsoap@lemm.ee
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            3 days ago

            Those two things are memorisation tasks. Maths is not about memorisation.

            You are not supposed to remember that the area of a triangle is a * h / 2, you’re supposed to understand why it’s the case. You’re supposed to be able to show that any triangle that can possibly exist is half the area of the rectangle it’s stuck in: Start with the trivial case (right-angled triangle), then move on to more complicated cases. If you’ve understood that once, there is no reason to remember anything because you can derive the formula at a moment’s notice.

            All maths can be understood and derived like that. The names of the colours, their ordering, the names of the planets and how they’re ordered, they’re arbitrary, they have no rhyme or reason, they need to be memorised if you want to recall them. Maths doesn’t, instead it dies when you apply memorisation.

            Ein Anfänger (der) Gitarre Hat Elan. There, that’s the Guitar strings in German. Why do I know that? Because my music theory knowledge sucks. I can’t apply it, music is all vibes to me but I still need a way to match the strings to what the tuner is displaying. You should never learn music theory from me, just as you shouldn’t learn maths from a teacher who can’t prove a * h / 2, or thinks it’s unimportant whether you can prove it.

              • barsoap@lemm.ee
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                3 days ago

                Nothing. And that’s why people don’t write equations like that: You either see

                     4
                6 + ---
                     2
                

                or

                 6 + 4
                -------
                   2
                

                If you wrote 6 + 4 / 2 in a paper you’d get reviewers complaining that it’s ambiguous, if you want it to be on one line write (6+4) / 2 or 6 + (4/2) or 6 + ⁴⁄₂ or even ½(6 + 4) Working mathematicians never came up with PEMDAS, which disambiguates it without parenthesis, US teachers did. Noone else does it that way because it does not, in the slightest, aid readability.

        • dohpaz42@lemmy.world
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          3 days ago

          You might be smart, but you’re still wrong about the importance of order of operations; especially in algebra.

          As far as teachers go, you’re being a dick by generalizing all (US) teachers are lazy and do not understand math.

          Pro tip: opinions are like assholes; you too have one, and yes it too stinks.

        • baines@lemmy.cafe
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          3 days ago

          just say you like the smell of your own farts, it would be less text for us to read for the same result