Because I’m a math teacher, my services as demystifier of mathematical phenomena are sometimes requested by family and friends who find themselves sufficiently mystified by something mathematical. Recently I’ve had a few people send me the link to the YouTube video, “How do japanese multiply??” [sic]
Based on some of the comments (e.g., “What the [flip] is this wizardry?”), there are at least a few people in the world who might like an explanation. Here’s the original video, followed by my narrated solution, plus, for the nerdily inclined, a bonus example in base 6! Can you imagine anything more fun?
Actually, if you want a much more interesting multiplication algorithm, take a look at Russian Peasant Multiplication. Now that’s some [binary] wizardry.
…and the response…