Right vs. wrong answers

In Classroom Discussions, the authors write about the importance of mathematical reasoning. It's important for students to have the ability to decide for themselves whether their answers are right or wrong. Instead of telling students whether the answer is or isn't correct, invite others to agree or disagree. Offer multiple answers (generated from your students' work, or even from teacher-created samples) and allow students to explain why they believe one of the answers is the correct one.