Can you help me with my maths?

Last week's post about parents and homework reminded me of a story (possibly apocryphal) which I heard a good few years ago concerning a local school. It was said that a particular teacher was in the habit of marking homework which had been done to a high standard "Good work - WDM". Nobody quite knew what this meant, and when the teacher left to take up a post elsewhere, he was asked to explain it. "Oh" he said "it stands for Well Done Mum"!