The start of a maths lesson, 197{ahem!}; a maths teacher flinging marked homework jotters at pupils. He arrives at that belonging to a Boy Lurker...
Boy Lurker! 3 times 3?
Boy Lurker, rapidly and confidently, six sir.
*A moment's silence for the awful truth to sink in.*
A pitying look from the maths teacher as the Boy Lurker cringes at his desk whilst his school-fellows pour (well deserved) scorn and derision upon him.
I had made _exactly_ the same error in the homework, I'd done all the hard stuff (chiz algebra) perfectly but stuffed up basic arithmetic. Over the years MrsLurker has come to recognise that my arithmetic is a little, umm, fuzzy and does our accounts. It's probably for the best.