The distinction between careless and confused matters most before punishment is assigned.

Carelessness and confusion produce the same wrong answer and require opposite responses. One needs attention and the other needs explanation, and punishing the second as though it were the first teaches a student that not understanding is a moral failure. The distinction is easy to make and routinely skipped.

Before responding to any mistake, ask what happened. It takes one question. This applies at work as much as in a classroom, where the same error is treated as negligence when it was often simply a gap nobody had filled.