• lauha@lemmy.world
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    3 months ago

    Your obviously is only a convention and not everyone agree with that. Not even all peogramming languages or calculators.

    If you wanted obviously, it would have to have different order or parentheses or both. Of course everything in math is convention but I mean more obvious.

    2+2*4 is obvious with PEDMAS, but hardy obvious to common people

    2+(2*4) is more obvious to common people

    2*4+2 is even more obvious to people not good with math. I would say this is the preferred form.

    (2*4)+2 doesn’t really add more to it, it just emphasises it more, but unnecessarily.

    • Septimaeus@infosec.pub
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      3 months ago

      Honestly that’s my pet peeve about this category of content. Over the years I’ve seen (at least) hundreds of these check-out-how-bad-at-math-everyone-is posts and it’s nearly always order of operations related. Apparently, a bunch of people forgot (or just never learned) PEMDAS.

      Now, having an agreed-upon convention absolutely matters for arriving at expected computational outcomes, but we call it a convention for a reason: it’s not a “correct” vs “incorrect” principle of mathematics. It’s just a rule we agreed upon to allow consistent results.

      So any good math educator will be clear on this. If you know the PEMDAS convention already, that’s good, since it’s by far the most common today. But if you don’t yet, don’t worry. It doesn’t mean you’re too dumb to math. With a bit of practice, you won’t even have to remember the acronym.

      • bisby@lemmy.world
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        3 months ago

        Most actual math people never have to think about pemdas here because no one would ever write a problem like this. The trick here is “when was the last time I saw an X to mean multiplication” so I would already be off about it

        1 + 1/2 in my brain is clearly 1.5, but 1+1÷2 doesn’t even register in my brain properly.

          • bisby@lemmy.world
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            3 months ago

            And yet Maths textbooks do! 😂

            “No one” in this context meant “no one who actually does maths professionally.”

            In a Maths textbook

            Right, and I have decades of maths experience outside of textbooks. So it’s probably been 20 years since I had a meaningful interaction with the × multiplication symbol.

            You don’t know that the obelus means divide??

            I clearly know what the symbol means, I demonstrated a use of it. But again, haven’t had a meaningful interaction with the symbol in 20 years, and yet I deal with / for division daily.

            When I see 1+½ i can instantly say “one and a half”, but when I see 1 + 1 ÷ 2 i actually have to pause for a moment to think about order of operations. Same with 1+2x vs 1 + 2 × x … one I recognize the structure of the problem immediately, and one feels foreign.

            The point is that people who do maths for a living, and are probably above average in maths, tend to write things differently than people who are stopped their maths education in high school (or lower), and these types of memes are designed around making people who know high school maths feel smart. People who actually know maths don’t need memes to justify being better at maths than the rest of the public.

            • “No one” in this context meant “no one who actually does maths professionally.”

              No it doesn’t. Everyone who does Maths professionally does it the same way as in Maths textbooks 🙄

              When I see 1+½ i can instantly say “one and a half”

              And that would be wrong. It’s 1 plus one half. 1½ is one and a half.

              when I see 1 + 1 ÷ 2 i actually have to pause for a moment to think about order of operations

              You don’t know to Divide before Adding??

              one I recognize the structure of the problem immediately, and one feels foreign.

              Says person with “decades of maths experience outside of textbooks” 🙄

              The point is that people who do maths for a living

              That would be me

              are probably above average in maths, tend to write things differently than people who are stopped their maths education in high school (or lower)

              Nope. We all write it the same way as we were taught, even those who have done Maths at University (also me).

              these types of memes are designed around making people who know high school maths feel smart

              No, they’re designed around getting those who have forgotten the rules to argue about it. i.e. engagement bait

      • having an agreed-upon convention absolutely matters for arriving at expected computational outcomes,

        Proven rules actually

        we call it a convention

        No we don’t - the order of operations rules

        it’s not a “correct” vs “incorrect” principle of mathematics

        The rules most definitely are

        It’s just a rule we agreed upon to allow consistent results

        proven rules which are true whether you agree to it or not! 😂

        any good math educator will be clear on this

        Yep

        If you know the PEMDAS convention already, that’s good, since it’s by far the most common today

        No it isn’t.

        But if you don’t yet, don’t worry

        As long as you know the rules then that’s all that matters

        • Septimaeus@infosec.pub
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          3 months ago

          Dear Mr Rules,

          I’m not sure what motivates you to so generously offer your various dyadic tokens of knowledge on this subject without qualification while ignoring my larger point, but will assume in good faith that your thirst for knowledge rivals that of your devotion to The Rules.

          First, a question: what are conventions if not agreed upon rules? Second, here is a history of how we actually came to agree upon the aforementioned rules which you may find interesting:

          https://www.themathdoctors.org/order-of-operations-historical-caveats/

          Happy ruling to you.

          • knowledge on this subject without qualification

            I’m a Maths teacher with a Masters - thanks for asking - how about you?

            while ignoring my larger point

            You mean your invalid point, that I debunked?

            what are conventions if not agreed upon rules?

            Conventions are optional, rules aren’t.

            here is a history of how we actually came to agree upon the aforementioned rules which you may find interesting

            He’s well-known to be wrong about his “history”, and if you read through the comments you’ll find plenty of people telling him that, including references. Cajori wrote the definitive books about the history of Maths (notation). They’re available for free on the Internet Archive - no need to believe some random crank and his blog.

    • Your obviously is only a convention

      Nope. Rules of Maths

      it would have to have different order or parentheses or both.

      Neither. Multiplication is always before Addition, hence “obviously”

      Of course everything in math is convention

      Nope. The vast majority of it is proven rules

      2+(2*4) is more obvious to common people

      Weird then how many people were able to get this right without brackets for centuries before we started using brackets in Maths (which we’ve only had for 300 years)