And if so, what did you do when your pupils told you?
And showed you the worksheet in their book?
Did you
a) Realise your mistake, and either teach a new lesson or do some revision
b) Carry on, ignore your pupils, and do the same lesson?
Because that's allegedly what happened at DS's school recently.
I get why it could happen. Tired teachers, over worked and under pressure.
But when your pupils tell you that they've done this before....