Describes the typical eighth-grade geometry curriculum (with regard to teacher emphasis on content, time allocations, instructional methodologies, the use of manipulatives, and compared to current research models) of typical (n=109) and enriched (n=23) mathematics classrooms in the United States based on data from the IEA Second International…

Described are inconsistencies, definitions, and examples and their complex relationship which can be used to interpret students' reactions to the geometric tasks used to investigate inconsistencies in student thinking. Discusses the nature of definitions, the value of precise vocabulary, the use and limitations of prototypes, and the power of…