The author wants her students to see any new mathematics--fractions, negative numbers, algebra--as logical extensions of what they already know. This article describes two students' efforts to make sense of their conflicting interpretations of 1/2 × -6, both of which were compelling and logical to them. It describes how discussion, constructing…

Dot arrays provide opportunities for students to notice structures like commutativity and distributivity, giving these properties an image that can be manipulated and explored. These images also connect to ways that we organize discrete objects in everyday life. This article describes how the authors developed an array of dot tasks that have been…

"Concept study" is described in this article as a collaboration of teachers to investigate images, analogies, metaphors, exercises, and other experiences that are used to support students' understandings of concepts. The discussion is illustrated with the examples of multiplication and prime numbers. (Contains 3 figures.)

This article discusses the algorithm for multiplication that is referred to as lattice multiplication. Evidence of how the author's preservice students' conceptual understanding of the algorithm grew through the semester is given. In addition, the author extends the conceptualization of the algorithm from the multiplication of whole numbers to the…