

Clever Multiplication Technique (Video) - Gibbon
http://www.hostedfile.com/videos/10622/new-multiplication-technique.html

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mrtron
Very cool, basically a visualization of the standard multiplication technique.

For ##x## it really helps for the 2nd step. A number like 18x31 is really
quick to do building backwards with this, 8, 25 ,3; so 558. With more
rounding, I think my traditional method of rounding and taking into account
the difference is better, 99x99 being the worst case example.

I imagine if you practiced even a little you could do 2x2 and 3x3 numbers in a
snap.

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cliff
Turns out this isn't 'new' by any means, but it is definitely cool. (i have no
evidence to back up this statement other than childhood memory)

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qwzybug
Cute, but having trouble seeing how that's any better than the grade-school
algorithm it's based on. (What, we have to add in unary now? This is
progress?) You still have to carry, you still perform n^2 operations for
n-digit numbers; the difference is you need a lot more paper and time, and it
makes for a better video. (And God help you if you have to multiply any
nines...)

Now, someone show me a convolution-based n log n multiplication algorithm you
can do quickly with pen and paper and I'll be impressed. :)

