ABSTRACT
This chapter argues that an inadequate understanding of fractional parts as units of measure is the primary conceptual reason why students find fraction learning difficult and confusing. It discusses the several other hypotheses that have been advanced to explain students' difficulties with fractions. First, the idea derived from counting-based accounts of numerical development, that fractions are problematic because they do not conform to the ideas about numbers that are the basis for earlier forms of numerical thinking, particularly counting, is examined. Second, the idea that fractions are conceptually complex in that they involve a cluster of distinct, albeit interrelated, subconstructs is briefly discussed. Third, the idea that the information-processing demands of fractions overwhelm students, particularly in the elementary grades, is considered. The chapter addresses the conceptual links between fraction learning and earlier mathematical learning, highlighting the potential ramifications of the way in which whole-number arithmetic is taught for later fraction learning.
