The calculus concepts of concavity and inflection points are often given meaning through the shape or curvature of a graph. However, there appear to be deeper core ideas for these two concepts, though the research literature has yet to give explicit attention to what these core ideas might be or what it might mean to "understand" them.…

In classrooms tests, students are regularly required to demonstrate their understanding of mathematical concepts. When children encounter problems in demonstrating such understanding, it is often not clear whether this is because of the language of the teachers' questions and instructions or a genuine non-understanding of the concept itself. This…