Birthday

Recently I joined a mailgroup at work called “Stuff” designed for off-topic dicussions and want-ads. Today I got a couple of great deals. First, a 2.1 speaker set for $10. The seller said they didn't work the last time he tried them. They didn't work for me at first. So…

Inspired by 's Rubik cube antics, I picked one up myself last week. When I was a kid, the most I could do was one side. So this time I set about solving it properly. I'm not interested in solving it really quickly, just in being able to solve it….

One of my colleagues came into my office the other day, and said to me: If p is prime and greater than 3, prove that p² – 1 is divisible by 24. Interested readers might want to try this for themselves: it’s not particularly difficult. Of course I started in…