• nuko147@lemm.ee
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      1 month ago

      My brain works like

      100 - 100*(10/100) = 90

      90 + 90*(10/100) = 99

          • Nakoichi [they/them]@hexbear.net
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            1 month ago

            Ah I’m in US so maybe this is one of those rare occasions where the US took an actually good idea from europe. I hear it’s a better system.

          • christian [he/him, any]@hexbear.net
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            1 month ago

            I don’t think I was ever taught this, but that’s more or less how I do arithmetic. More precisely, my mental arithmetic would transcribe to:

            47 + 36 = 47 + (30 + 6) = (47 + 6) + 30 = 53 + 30 = 83

              • christian [he/him, any]@hexbear.net
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                1 month ago

                I think they’re essentially the same thing. I don’t really have a process for what order to work in, just intuition for what will be the least friction. If it were big enough numbers I’d probably go through a second time in a different order of addition to double-check.

                It’s just weird that I’ve done a lot of math and never really thought about that process. That’s why you’d ideally want any math below precalc to be taught by someone with a math education degree rather than someone who just has a math degree. When you’ve used the concepts you’re teaching with enough regulatity that they’re second nature, you have very poor intuition for which concepts will trip up someone learning for the first time.