• silent_water [she/her]@hexbear.net
    link
    fedilink
    English
    arrow-up
    10
    ·
    edit-2
    7 months ago

    I kind of hate PEMDAS because multiplication and division are the same thing (division is multiplication by the reciprocal) and addition and subtraction are the same thing (subtraction is addition of the negation). moreover, multiplication and addition are commutative with themselves. so it should really be PEMA. lastly, if it’s fucking ambiguous in any way, don’t write it that way. just use parentheses. the notation that puts divisors in the denominator completely disambiguates everything.

    just learn what associativity, commutativity, and the distribution law are in the first place and you’ll understand why something like PEMDAS exists. it’s a notational trick to make it clear where those laws can be applied. when you leave the realm of numbers, some or all of these laws will stop applying and you need to still learn how to calculate the answer. matrices don’t have commutative multiplication and if it won’t associate, stop and find a different way to solve a different way to solve your problem because nope nope nope nope (fucking programmers breaking associativity in binary operations because “math is hard” - no removed, what’s hard is trying to work out what the hell your operation does).

    in summary, PEMDAS is liberalism and fuck javascript.

    • Zezzy [she/her]@hexbear.net
      link
      fedilink
      English
      arrow-up
      4
      ·
      7 months ago

      We were taught PEMDAS as parentheses, exponentiation, multiplication OR division, addition OR subtraction. I don’t know if it was changed at some point but I don’t know anyone who was taught that multiplication comes before divison

      • silent_water [she/her]@hexbear.net
        link
        fedilink
        English
        arrow-up
        4
        ·
        7 months ago

        I’m talking about the implied ordering from the name. I’m saying there’s no sense in including division or subtraction at all because they’re not actually different from multiplication or subtraction and we’re better off teaching the underlying laws in the first place.