Hey, guys, look at this!

[conuly]

This is the coolest method of multiplication I've ever seen. I knew, of course, that you could grid multiply, but I figured any big number would mean doing 123 lines up and 321 lines across or whatnot!

Also here. Taken from here.

Comments

[sayga.livejournal.com]

That is SO COOL. Have you tried it with lots of other numbers? I showed this to Daniel, who has always struggled with math, and he was completely impressed!

[conuly]

I'm still not sure how they group the angles. I think I have it, but....

[oloriel.livejournal.com]

Hmm. It's certainly fascinating, but it seems a veeery long-winded way of multiplying. I'd have arrived at the 273 conclusion in my head faster than it takes her to count all the intersections, and in the second example I would likewise have arrived at the product with old-fashioned Western-style multiplication much faster... though I suppose this can be done faster, if you're practiced and not going slow to explain it on camera ;)

But it is certainly easy to do. I suppose the usefulness just depends on the purpose - whether you just want to arrive at the product eventually, or whether you have ten minutes for 30 problems...

[queenlyzard.livejournal.com]

This is awesome and amazing... particularly to someone like me who does NOT think in math. I must learn how to do this-- I think it will save me a lot of time.