Error is normal, and making mistakes is a necessary part of learning. In Teach Like a Champion, Doug Lemov's brilliant distillation of 49 techniques for teachers to use to improve student performance, he writes that teachers should normalize error and avoid chastening students for getting it wrong. (Lemov's book has application far beyond the classroom):
"Error followed by correction and instruction is the fundamental process of schooling. You get it wrong, and then you get it right. If getting it wrong and then getting it right is normal, teachers should Normalize Error and respond to both parts of this sequence as if they were totally and completely normal. After all, they are.
WRONG ANSWERS: DON'T CHASTEN; DON'T EXCUSE
"Avoid chastening wrong answers, for example, 'No, we already talked about this. You have to flip the sign, Ruben.' And do not make excuses for students who get answers wrong: 'Oh, that's okay, Charlise. That was a really hard one.' In fact, if wrong answers are truly a normal and healthy part of the learning process, they don't need much narration at all.
"It's better, in fact, to avoid spending a lot of time talking about wrongness and get down to the work of fixing it as quickly as possible. Although many teachers feel obligated to name every answer as right or wrong, spending time making that judgment is usually a step you can skip entirely before getting to work. For example, you could respond to a wrong answer by a student named Noah by saying, 'Let's try that again, Noah. What's the first thing we have to do?' or even, 'What's the first thing we have to do in solving this kind of problem, Noah?' This second situation is particularly interesting because it remains ambiguous to Noah and his classmates whether the answer was right or wrong as they start reworking the problem. There's a bit of suspense, and they will have to figure it out for themselves. When and if you do name an answer as wrong, do so quickly and simply ('not quite') and keep moving. Again, since getting it wrong is normal, you don't have to feel badly about it. In fact, if all students are getting all questions right, the work you're giving them isn't hard enough.