I recently picked up a book called Secrets of Mental Math written by one of my college math professors. It has very practical advice on how to learn to multiply large numbers in your head. He gives practical advice on necessary skills like addition, subtraction, and related mathematical trivia. To practice multiplying numbers in your head, I’ve created a fast, simple javascript tool which you can access from your phone at http://leodirac.com/mathquiz .
The author of the book is Arthur Benjamin. He gave a demonstration of his mad skillz at TED a while back, which I’m embedding here because it’s awesome.
Migrating this blog has been fun because it’s forced me to look over a lot of the old content I’ve written. A couple years ago I found Benjamin’s Ted talk, which has inspired all this craziness. I think it’s good to keep the brain fresh by taxing skills that one might not have used in a while.