Percentages have proven to be a challenging concept in school mathematics. At the surface, a percentage is merely a rational number, representing a ratio between a number and 100. At the conceptual core, however, a percentage is sensitive to the context, making sense with respect to a network of related quantities. In the effort of the authors to…

Many preservice teachers come into teacher education programs with a rule-based view of mathematics, a view that is to a large extent indicative of their previous school experiences. In teaching preservice elementary school teachers, this author has used his instrumental understanding as the starting point for rich discussions about the…

This study sought to examine the development of prospective secondary mathematics teachers' Technological Pedagogical Content Knowledge as they worked individually and in small groups to develop and present lessons with dynamic mathematics software. In a three-semester long study, data were collected from 68 prospective secondary mathematics…