In this brief review, research on varying types of instructional materials is summarized. The evidence indicates that the textbook is the most widely used instructional material, and few teachers appear to use any other materials more than five times a year. Research findings on the value of the use of manipulative materials seems clear: they have a high probability of increasing achievement, and appear to be essential in providing a firm foundation for developing mathematical ideas. While textbooks and tests shape the curriculum, studies indicate that the match of topics between the two cannot be taken for granted. While most children at all grade levels have access to or own calculators, few teachers actually use them in the mathematics classroom. Nevertheless, achievement scores are as high or higher when calculators are used for mathematics instruction as when they are not used. The usefulness of computers is accepted, but the task of integrating them into the curriculum has just started. Each of the findings is discussed, with illustrative references cited. (MNS)