What is Replacement

This chapter reports on a project in which elementary mathematics preservice teachers visualized lessons through an online animation platform. Preservice teachers at two universities engaged in an extensive project that translated printed mathematics curricular materials into visualizations of enactment. The project centered on preservice teacher-created animations as a way to extend the lesson planning process and more closely approximate actual decisions of teaching practice, including representations used, student contributions, and mathematical understanding. Project components are described with an emphasis on the role of animations as an extension of lesson planning. The intent is to understand the ways in which the technology platform illuminated preservice teachers' curricular decision making as they transitioned from a written lesson plan to animated lessons. Consideration is made for how the technology may provide transformational opportunities that otherwise may not have occurred.