I was one of the "guinea pigs" subjected to the Cambridge University's "School Mathematics Project" when I was 11 in 1965. We did modern maths, with sets and matrices etc. With the latter I always had premonitions of men in shades and lots of green numbers flashing before my eyes.

My teacher was a certain Dave "three hundredweight" Hanneman, so-called because it was rumoured that that he could lift this amount above head height.