Proving in school geometry is not just about validating the truth of a claim. In the school setting, the main function of the proof is to convince someone that a claim is true by providing an explanation. Students consider proving to be difficult; in fact, they find the very concept of proof demanding. Proving a claim in planar geometry involves…

Assigning difficulty level indicators to the knowledge units helps the learners plan their learning activities more efficiently. This paper focuses on how to use the topology of a knowledge map to compute and rank the difficulty levels of knowledge units. Firstly, the authors present the hierarchical structure and properties of the knowledge map.…

Describes attempts to instruct 12 children, aged between 10 and 11, during a 12-hour course in LOGO that proper attention should be paid to the external angles through which the turtle rotated. Results suggest that using LOGO to draw closed figures may lead to confusions about angle that are not amenable to conventional intervention techniques…

Suggests one possible way to combine the technological facility of the computer with students' natural abilities for concept formation. Describes the software the "Geometric preSupposer." (PK)

Previous work has identified four areas of difficulty that students seem to have with the topic of similarity: (1) understanding the definition of similarity; (2) proportional reasoning; (3) dimensional growth relationships; and (4) correspondences in right triangle similarity. This paper reports the results of an investigation into high school…