“Students hide their mistakes from me”

Hiding a mistake is a sensible move, and students learn it early. A visible error can cost something real: a correction in front of friends, a sigh, a book handed back covered in red. So they rub out the working before you reach the desk, keep the page angled away, and tell you they are fine. Nobody is being dishonest in any deep way. They are managing risk. Some ordinary checking habits feed the pattern too: asking "does everyone understand?" collects self-reports, and a student who feels at risk says yes.

The pattern holds because in the moment it suits everyone. You ask, they say yes, the lesson keeps its pace, and the real picture stays in the books until marking, when the moment to act on it has gone. Changing that means making mistakes visible and making them safe, and the techniques below work on both fronts: some change how you check, so the evidence comes from the work itself rather than from what students are willing to admit, and some change what a mistake costs in your room, so there is less reason to hide one.