ABSTRACT
Problem solving is often done in the context of an external display. Often there are the physical objects that are part of a problem situation. Alternatively the solver may construct equations and diagrams as an aid to solving the problem. The purpose of this chapter is to describe a model that explicates the role of these displays, particularly for simple every-day problems and for school mathematics and science. In many of these tasks, skillful use of the display seems to be the dominant problem-solving process. This display-based model of problem solving both explains why certain tasks are easy and why particular mistakes are common.
