Students learn from their mistakes, they say.

I agree. They learn something. But often what they are learning is not what the teacher thinks she is teaching.

M. Moriarty said it well in a comment on an earlier post:

To this day I cannot bear a red pen… it signals math failure to me – and try as I might – I never did learn from my many many mistakes in grade school math – what I learned was that I wasn’t very good at math and that after a while it really wasn’t any use to try…. Continue reading →