Defines visualization as the product and the process of creation, interpretation, and reflection upon pictures and images. Analyzes, exemplifies, and reflects upon the many different and rich roles that it can and should play in the learning and doing of mathematics. Discusses limitations and possible sources of difficulties visualization may pose…

Focuses on the role of tools, provided by a computer microworld (C.AR.ME), on the strategies developed by 14-year-old students regarding the concept of conservation of area of a non-convex polygon. Indicates that the nature of the tools used affected the nature of solution strategies that students constructed. (Author/KHR)