Whilst teaching my class of 9 and 10 year olds about idioms, and literal/figurative meaning...

H: Mrs B, what does 'lose your rag' mean?
Me: Well, if I said "H, I'm going to lose my rag with you in a moment!", what would I mean?"
H: That you didn't have any clothes on?

Oh, how I laughed!! :)

The same chap also said to me way back in September "But Mrs B, I don't know how to do borrowing on a calculator!!" when using a calulator to solve subtraction problems...!