What's new

Difficulty: Extreme 123,456,789 is not a prime number. Is it possible to reorder its digits to give a prime number?

Late last year, Jonathan Pace’s computer found something special. Jonathan is an electrical engineer who also manages computers for charities, so he has a lot of computers, but this one was nothing out of the ordinary. Except for one thing: the computer was running software from the Great Internet Mersenne Prime Search

For over a thousand years, people have been drawing intricate woven patterns known as Celtic knots. As we’re about to find out, there’s a lot of maths involved!