Graded Troubleshooting (GTS) is a powerful routine that teachers can use easily to engender students' metacognitive thinking and boost their understanding of mathematics concepts and procedures. This article describes a new GTS activity designed to prompt students to efficiently exploit worked examples when asked to diagnose erroneous examples…

Students are expected to use the Cartesian plane to represent and reason about mathematical concepts such as number systems, geometric figures, and functions. However, the simplicity of representing mathematical concepts that the Cartesian plane provides can cause us to overlook the difficulties many students have in constructing and using it.…