• Septimaeus@infosec.pub
    link
    fedilink
    arrow-up
    11
    arrow-down
    2
    ·
    9 days 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.

    • 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
        link
        fedilink
        arrow-up
        1
        arrow-down
        1
        ·
        3 hours 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.

          • Septimaeus@infosec.pub
            link
            fedilink
            arrow-up
            1
            ·
            2 hours ago

            Dear colleague,

            By qualification I meant explanation. My doctorate is irrelevant to the truth.

            Since you asked, my larger point was about the unhelpful nature of this content, which makes students of math feel inordinately inferior or superior hinged entirely on a single point of familiarity. I don’t handle early math education, but many of my students arrive with baggage from it that hinders their progress, leading me to suspect that early math education sometimes discourages students unnecessarily. In particular, these gotcha-style math memes IMO deepen students’ belief that they’re just bad at math. Hence my dislike of them.

            Re: Dave Peterson, I’ll need to read more about this debate regarding the history of notation and I’ll search for the “proven rules” you mentioned (proofs mean something very specific to me and I can’t yet imagine what that looks like WRT order of operations).

            If what riled you up was my use of the word “conventions” I can use another, but note that conventions aren’t necessarily “optional” when being understood is essential. Where one places a comma in writing can radically change the meaning of a sentence, for example. My greater point however has nothing to do with that. Here I am only concerned about the next generation of maths student and how viral content like this can discourage them unnecessarily.

    • bisby@lemmy.world
      link
      fedilink
      arrow-up
      8
      arrow-down
      2
      ·
      9 days 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
          link
          fedilink
          arrow-up
          1
          ·
          2 hours 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.

      • Septimaeus@infosec.pub
        link
        fedilink
        arrow-up
        4
        ·
        edit-2
        8 days ago

        Right, and that clue IMO unravels the more troubling aspect of why this content spreads so quickly:

        It’s deliberately aimed at people with a rudimentary math education who can be made to feel far superior to others who, in spite of having roughly the same level of proficiency, are missing/forgetting a single fact that has a disproportionate effect on the result they expect.

        That is, it’s blue-dress-level contentious engagement bait for anyone with low math skills, whether or not they remember PEMDAS.

    • Jarix@lemmy.world
      link
      fedilink
      arrow-up
      2
      ·
      8 days ago

      I learned BEDMAS. Doesn’t really change your comment other than effectively “spelling” of a single term