Often, when middle-school students make mistakes, they tend to erase their work and record the correct answer without trying to understand what led to the mistake. In response, this article describes three opportunities educators can leverage for engaging students in the processes of reasoning and sense making about mathematics.

In this article, three instructional situations demonstrate the value of using an "unknown" student's work to allow the advancement of students' mathematical thinking as well as their engagement in the mathematical practice of critiquing the reasoning of others: (1) introducing alternative solution strategies; (2) critiquing inaccuracies…

When the word problems of forty-five sixth-grade students were examined, multiple levels of understanding and misunderstanding multiplication were exposed. The purpose of this article is to demonstrate the potential of problem writing as a technique for assessing the depths of students' mathematical understandings. Discussions include sample…