Japanese Long Multiplication

9 comments:

  1. This method is not Japanese as far as I know. A generalization of this method was used by Babbage used it to build his differential engine:

    http://www.computerhistory.org/babbage/howitworks/

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  2. or you get a calculator and be done in 2 seconds...

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    Replies
    1. I would be quite impressed if you managed to get a calculator AND type in the equation within 2 seconds.

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    2. are you trying to tell me you don't have a necklace calculator on at all times?

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  3. now try that with a simple multiplication like: 8 x 9
    lol than you need to count 56 crossing lines (cross points)

    but still a cool way to multiply!

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  4. easy with small digit like 1 2 3, but with 7 8 9 will be a pain to count and draw

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  5. Is it sad I can do this type of math in my head without counting line intersections?

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  6. I don't think I've ever seen anyone in Japan using this method.

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