Archive for February 15th, 2008

Multidigit multiplication: vertically and crosswise

February 15, 2008

I think I have a new favorite way to multiply numbers: the vertically and crosswise technique. I learned about it from George Gheverghese Joseph’s Crest of the Peacock [a book that is sadly out of print], and was recently reminded of just how cool it is.

Click here to find out how it is done and why it works

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