Precisely who is in the classroom matters...

More news from the Eastern Front (i.e. Intermediate 1 Mathematics with a class where at least half have no interest in being in the room).
Sickness has decimated the group. Actually, no it hasn't. It's even worse than that - only half the group was in today. If you understand that, go straight to the next paragraph. If you didn't get it: decimate means "remove (kill) one in ten", despite common usage, which seems to suggest decimate means leaving only one in ten standing, or something like that. Put it this way, if you are ever captured by a James Bond villain and given the choice "Either choose half of your number to die or I'll decimate you", choose decimation. As long as you are confident the villain uses English precisely (or nicely, in its original meaning).
Anyway, pedantry aside, near half of my S5 class was off today. Funnily enough the group present was almost complementary to the bunch who appeared on Friday. So I had an easy lesson: repeat what I did on Friday...... and the notes and graphs I'd drawn were still on the board. So there's a good reason not to wipe the board clean after every lesson :)
More importantly, the chattering girls were all absent (not all the girls, just the ones with the biggest propensity to chatter and the biggest chips on their shoulders - one on each of course, perfectly balanced). So the ones who wanted to work could do so, while I concentrated on the two groups with some common members: those who really do need help all the way and those who simple like to avoid having to work.
Result? More learning, albeit by fewer pupils. How do I work that equation out? And should I be persuading them not to get 'flu jabs?