The x factor

Firstly, from now on I'll be moving all those deadly dull poker posts to a separate blog which I've called Plutoman's Poker Planet, so you'll be spared all that badugi bollocks in future. Phew!

On Tuesday night I gave an hour's tuition to a 16-year-old Takapuna Grammar boy. He'll be doing the same exam as the girl from Remuera, only he's not quite at her level. His arithmetic was fine but his algebra needed a lot of work. I asked him to solve the equation (x-4)/2 = 7 for x. "Can't I just say it's 18? he said. Well, yes I suppose, although I'm not sure whether you get all the marks in the exam if you just slap down the answer. I then gave him the very similar expression (x-4)/2 = a and asked him to make x the subject, but he was all at sea there. I can understand how he finds the transition difficult. I always found numbers easier to handle than x's and y's. But I think a major reason why a lot of people find algebra difficult is that they just learn a bunch of rules to get them through their next test or exam, without knowing why they're applying those rules. For instance this kid could solve a quadratic equation like x² + 7x + 10 = 0 with no trouble, by finding two numbers that add to give 7 and multiply to give 10, but didn't know why that method worked. Of course he might also like to know why you'd want to solve a quadratic in the first place, and I can't help him there. I hope I can help him get through his exam in mid-November though.

After an icy blast early in the week things have warmed up again. On Saturday I've got the Asperger's group to look forward to.