While running today and listening to Marcus du Sautoy's Brief History of Mathematics, I felt a wave of nostalgia wash over me.
When I started learning maths seriously, I was a little bit too early for calculators. The teacher handed out a piece of apparatus which is completely unknown to schoolchildren today.
It was a white rule, about 18 inches long, and calibrated with numbers all along. A separate, thinner rule slid through the middle, so you could line up its numbers with those on the main one.
It was, of course, a slide rule. We used it for adding, multiplication, division, logarithms and plenty of other things.
When we had to work through an exercise, the class was taken over by the clattering sound of slide rules being slid, clicked and clunked back on the desks.
In my opinion, the slide rule puts you in charge of a calculation in a way that a calculator never can. You have to know how the working out is being done: the slide rule is like an extension of your brain, which just makes things easier.
The calculator, on the other hand, does it all for you. What's going on inside the calculator is a bit of mystery to most users.
After getting used to the ruler-shaped version, I was then introduced to the circular slide rule, which is a wonderful piece of kit.
After a previous bout of nostalgia I did a report for BBC2's Working Lunch which showed how the circular slide rule was still being made by Pooleys for pilots to use in navigation.
Why was I thinking of this? Du Sautoy's podcast was about Newton and I remembered that he was one of the early enthusiasts.
The mathematician Chris Sangwin has a useful slide rule history for anyone who is interested.
What happened to me next at school was that Sinclair came out with his pocket calculator - I think it was the Cambridge - and we all had to get one of those.
I still have my slide rule, though.