Content about “
arithmetic

Blog post

Maths in a minute: Clever sums

How would you go about adding up all the integers from 1 to 100? Tap them into a calculator? Write a little computer code? Or look up the general formula for summing integers?
Article

Having fun with unit fractions

The number 1 can be written as a sum of unit fractions, that is fractions with 1 in the numerator. But how long can we make such a sum?
News story

Pi day magic revealed

On March 14 2010 a mathematician and a magician teamed up to perform what they believed to be the world's largest live magic trick. The trick involved a thousand volunteers from the around the world who, using free choice, each came up with a number that was only known to themselves. And although the volunteer might be on the other side of the globe, the mathematician and the magician were able to read their mind and tell them which number they had chosen.

Article

Arithmetic, bones and counting

John Napier was a clever man indeed. Besides inventing the logarithm, he developed ingenious calculating devices that fully exploit the power of the positional system. In this article Chris Sangwin tells you how to make your own set of Napier's bones and perform mathemagic with an interactive checker board.
Article

The death of the lightning calculator

Runner up in the schools category Being good at mental arithmetic isn't going to gain you much street cred these days. But, as Owen Daniel explains, not so long ago it was a sure route to fame and fortune — even if you were a horse.