Polydactyly is a condition in which children are born with more than ten fingers or ten toes. The image at left is of the hands and feet of a Chinese boy who was operated on in 2010 to remove some of his digits because he was being bullied so much by his peers. In this particular case, he had 31 digits which was a world record.
As an interesting note, Goliath of Gath, the Philistine warrior (in)famous for his failed battle with David in the Bible, was polydactyl. We read in 1 Chronicles 20:6,
Again there was war at Gath, where there was a man of great stature who had twenty-four fingers and toes, six fingers on each hand and six toes on each foot …
I enjoyed your presentation and no it wasn’t too long. Each subtraction algorithm has its merit as you demostrated, but after learning the “one up and one down” method, I’m employing it because of its speed and ease of usage. Even my wife, who hates mathematics with a passion, thinks it’s too easy. I look forward to your future presentations on both multiplication and number theory. I read an introduction text book some twenty five years ago on number theory by Oystein Ore who taught at Yale for better than twenty years. So in closing, please produce these lectures and the longer the better. Thanks.
Dennis Bell (on a CCM YouTube video about How to Subtract (Large) Numbers Easily)
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