I’ve never seen this before – but according to this video, this is how the Japanese multiply. Or at least some of them. It’s pretty slick.
I remember years ago as a schoolboy being fascinated by something called, if I remember right, Trachtenberg Speed Mathematics, which was a system of calculating “tricks” that allowed for extremely fast mental computations of quite complicated arithmetical problems. There were hundreds of them, and they had all been figured out by a concentration camp inmate during WW2 as a means to keep himself sane.
I haven’t given any of this a single thought in decades, but I see here, now I just googled it, that it’s still around, and I did remember right, except I had the name slightly wrong. It’s powerful.
Anyway, back to the video. I love this kind of thing.
I’d love to know if they teach this method in school in Japan. Paging our Japanese correspondent … Mr. Salad … Mr Amoeba Salad … white courtesy telephone please !