• jtrek@startrek.website
    9·
    22 hours ago

    Today I leaned on whatever android calculator app I have, if you type 3+3x2 it does return 9. I didn’t think it was that sophisticated, and thought it just evaluated left to right like an old time calculator. Or at least, I think that’s how my old calculator worked.

    • Creat@discuss.tchncs.de
      10·
      21 hours ago

      Physical calculators for actual math (like used in schools) haven’t done that in a few decades. Even in the 90s.

      • jtrek@startrek.website
        2·
        20 hours ago

        The old calculator I just found in the desk, a canon HS-1000TG, does do the operations as you enter them.

        Entering 3+3x2= returns 12

        • Fredselfish@sh.itjust.works
          211·
          19 hours ago

          So that be correct answer, I mean if I were to do math in my head or on paper. Yet my calculator on the phone answered 9. What the fuck?

          • jtrek@startrek.website
            5·
            8 hours ago

            Math conventions say to do multiplication before addition. Writing it as “3+3*2” invites the error you made when you read left to write. There are clearer ways to write it (eg (2*3) + 3, but some people get kind of aggro about that.

          • LostCarcosan@lemmy.today
            11·
            17 hours ago

            If you do the math in your head and get 12, you did it wrong in your head. Did you not learn the order of operations in school?

    • tigeruppercut@lemmy.zip
      4·
      20 hours ago

      It’d be more surprising if the calculator apps were dumb enough to not do PEMDAS.

      Back in the day I had a math teacher tell us to check if a cheap calculator was coded competently by punching 2÷3×6. After 2÷3 when you pushed x it’d spit out 0.66666667 (because on those ones you couldn’t do more than one operator at a time). A decent one would store the actual value of 2/3 even though the display showed .6 repeating, so x6 would produce the proper answer 4. A poor one returned 3.99999996

      • MrShankles@lemmy.world
        3·
        15 hours ago

        I used to have anxiety about trusting a calculator’s output, and would end up doing the order of operations separately. It drilled them into my head though, I guess

    • ScreamingFirehawk@feddit.uk
      2·
      18 hours ago

      The calculator built into android works, why are you using some bootleg calculator that’s doesn’t know the order of operations?

    • taiyang@lemmy.world
      2·
      18 hours ago

      Interesting enough, it actually messes up some of my students because if you try to do a negative number squared without the parentheses, it does it the correct way of squaring and then multiplying by negative 1. Parentheses fixes it but so do dumb calculators that fuck up pedmas (or more accurately, calculators that only do once step at a time).