Japanese Multiplication

[Skybird]

That video is probably by a German and so he did not comment in language but points with the pencil so that it becomes clear what it is about.

The principle is as as simple as it is stu7nning. Multiplication without needing to do according math in your head!

http://www.youtube.com/watch?v=mLhSHauG9N4&feature=related

With German explanation, the same stuff:
http://www.youtube.com/watch?v=mSUhEL42njo&feature=related

[mapuc]

Amazingly, it is probably something I would show my niece. It is probably the simplest way to multiply in

Markus

[TorpX]

Interesting, but I think it's easier to do it in the usual way when you get into three digit numbers.

[TarJak]

Although it probably works with numbers larger than 3, the time and effort of drawing up to 9 lines for each digit wouldn't make it worth using for 999x998 for example.

Pretty neat trick for smaller digits though.

[Penguin]

quite interesting!

For people who have problems with the "traditional" multiplication, there is also the Indian method: http://www.youtube.com/watch?v=Sk8JXuLp6CI
The vid's in German only, but as math is an universal language, it should be self-explanatory.