Misconceptions about density of decimals: insights from pre-service teachers’ work

This is a pre-print of a paper from Konferensi Nasional Metematika XIV 2008 published by Indonesian Mathematical Society (IndoMS). http://knm14.wordpress.com/Extensive studies have documented various difficulties with, and misconceptions about, decimal numeration across different levels of education. This paper reports on pre-service teachers’ misconceptions about the density of decimals. Written test data from 140 pre-service teachers, observation of group and classroom discussions provided evidence of pre-service teachers’ difficulties in grasping the density notion of decimals. Incorrect analogies resulting from over generalization of knowledge about whole numbers and fractions were identified. Teaching ideas to resolve these difficulties are discussed. Evidence from this research indicates that it is possible to remove misconceptions about density of decimals