Perhaps the one unifying feature of all civilisations, from the pre-historic, to the present day is their understanding of numbers; with the ability to count, came the desire to compute. The oldest computational relic known to us is the Ishango Bone, found in Africa circa 18,000 BCE. But what happens if we dispose of our electric calculators, abacuses, and even our dead parent’s bones? Can we still achieve complex feats of arithmetic without these tools? The answer is not simple: whilst many of us strive to be able to remember the multiplication table for numbers greater than twelve, others have forayed far deeper into the world of mental arithmetic.

This talk will start with a historic look at the varying characters that shape the story of mental arithmetic, taking us from the 18th Century, through to the present day, before discussing what it is that makes a mental calculator different to the rest of us. Finally the talk will close with some simple arithmetical tricks for every day use, and to fool other eager lightning calculators with.

Owen daniel takes an informal look at the intriguing history of computation based on a paper of the same title, which was nominated for the first Plus New Writer Award for Mathematical Journalism, in 2006.

After, we go gradwards for banter and light refreshments

P.S. No that horse picture is not a mistake… Believe it or not, he was a lightning calculator (perhaps the greatest)… More on that at the discussion group.