Computer software with graphic representations of functions can teach algebraic concepts, or can blur or obscure concepts of great importance. Making good use and bad use of visual imagery are each discussed. Then a general theory of interpretation of graphs is proposed, and a list of examples is presented. (MNS)

Discussed are the range and balance of learning activities in the classroom, including discussion of the various roles of the people involved. The analysis is based on records of observations of 174 mathematics lessons with students aged 12-14; microcomputer use was integrated as a teaching aid. (MNS)