• hydroptic@sopuli.xyz
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    1 year ago

    You’re really asking whether commutativity of multiplication has ever helped anyone? Because that’s what this is.

    And yes it has helped me eg. estimate things or whatever along the years – but of course it’s not going to be some sort of magical mathematics trick where just by reversing the numbers it’ll always make things easier to calculate in your head

    • TAYRN@lemmy.world
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      1 year ago

      No, I think we all learned that multiplication is commutative in late elementary school, and obviously that’s an important thing to know.

      But I think the original post tried to make it out to be some magical mathematical trick, and I really don’t understand that. Maybe I misunderstood the post.

      Edit: wow, “commutative” is a really hard word to spell.

      • hydroptic@sopuli.xyz
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        1 year ago

        Yeah I think this is more about how you interpreted it, because it doesn’t look like others took it as being an absolute magic trick rule and neither did I.

        The Panzer of the Lake didn’t use the word “commutativity” (fuck that really is hard to spell), but it gave out some wisdom that applied that rule by saying that “percentages are reversible”: if the reverse of a percentage would be easier to calculate, you can use it and get the same answer. If it’s not easier, well, then you’re screwed 😁 Oooooor depending on the situation you can use the a × b% = a × b / 100 commutativity trick:

        7 × 8% = 0.56

        7 × 8 / 100 = 0.56