My failure to pass Maths O-Level three times (1973, 74 & 75) was not helped by my total misunderstanding of what a slide rule was meant for. If you wanted a straight line, with a little bobble in, then a slide rule was just that – forget that it was designed for complex multiplication and duplication; although, when I first got mine I thought it was broken as the middle bit kept sliding out.

Log tables were also useless if you were destined to regularly fail maths exams; however, if you had a slightly uneven desk, then a log table book was the ideal thing. Many restaurants use them for wobbly tables when they’ve run out of beer-mats.

My question is: what was the set-square for in the student Helix geometry set?  Compass, yes – if you’d forgotten your darts; protractor, yes – if you needed to draw half a moon or an ox-bow lake.  But a set-square?  It would remain, gathering dust like Miss Haversham’s dining room, in your protective plastic wallet, with no ostensible use.  Perhaps my school believed Tooting was going to be the source of budding architects?

It wasn’t until I failed my third maths O-level that I realised that trigonometry wasn’t a type of dinosaur, cosine was not a type of lettuce and Pythagoras’ theorem was not an ancient ruin just outside Athens.

Pi’s off, love!