• NegativeInf@lemmy.world
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    1 year ago

    I find this method is far faster for quick calculation of large numbers off hand. Or at least estimation. Choose a close round number you do know the maths for, then just add or subtract the relevant parts to get it to true.

  • andrewta@lemmy.world
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    1 year ago

    I do not have adhd. I do not have adhd. I do not have adhd.

    I do math like that in my head

    I do not have adhd.

    • funnystuff97@lemmy.world
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      1 year ago

      This is not necessarily an indication of ADHD. Being said, neurodivergence could lead people to attempting new solutions to tasks that they have never been taught, so it’s not like there’s no correlation. There’s just no direct causation here.

      Being said, this is a fantastic mental math shortcut, one that I wish would get taught more. Works for adding, subtracting, hell even multiplying and dividing. 16 × 20 is 20 more than 15 × 20, which is 300 + 20 = 320. Or perhaps you could say that 16 × 20 is 16 × 10 × 2 = 160 × 2 = 320. There are so many ways to break large numbers down into smaller, more manageable numbers for arithmetic, makes mental math a hell of a lot easier. And you can impress people with the ability to multiply large numbers in your head if you get good at it.

      57 × 41 is 57 more than 57 × 40, which is (7×40) more than 50×40. Well, 50×40 is 2,000, so 57×41 = 2,000 + (7×40) + 57 = 2,000 + 280 + 57 = 2,280 + 57 = 2,337. Admittedly that took me a minute and I did originally get 2,327, but you can see the process.

      • miss_brainfart@lemmy.ml
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        1 year ago

        If the symptoms you identify with have you struggle in life, then definitely get tested. Even if not, it’s still nice to know.

  • Milady@lemmy.world
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    1 year ago

    Look I have adhd I’m quirky. Don’t use something people struggle with as a quirky trait.

    • nyoooom@lemmy.world
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      1 year ago

      But what if I wanna shitpost about my ADHD?

      (don’t worry I know what you mean and yeah that post applies to everyone)

  • jumper775@lemmy.ml
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    1 year ago

    That’s just a normal shortcut for mental math. Break your problem into simpler problems then combine, in this case if one wants to know 7+6 this is being turned from 7+7=14, an easy problem to remember, into (7-1)+7=14-1=13.

    That doesn’t feel exactly right as it’s not exactly the way you think about it, but words can’t describe such inferences of thought other than to call them what they are which is not exactly how one’s thoughts reflect them.