Prime decomposition: Understanding uniqueness

Abstract This study investigates procedural and conceptual aspects in preservice elementary school teacher's understanding of the Fundamental Theorem of Arithmetic. The data were collected by the means of a written questionnaire and individual interviews. The results suggest that the idea of the uniqueness of prime decomposition is very difficult to grasp. Participants' responses indicated, either implicity or explicity, that a possibility of alternative prime decompositions was often not overruled, and this influenced students' ability to make inferences regarding factors and divisors of natural numbers. Some pedagogical implications are discussed.