Recently, a great deal of interest has been shown in communication in mathematics. The National Council of Teachers of Mathematics, in its Curriculum and Evaluation Standards for School Mathematics (1989), states that at all grade levels, students must learn to communicate mathematically. Science for All Americans: A Project 2061 Report (American Association for the Advancement of Science 1988) describes effective teaching of mathematics as teaching that emphasizes the development of students' abilities to communicate clearly in both oral and written work. Turning Points: Preparing American Youth for the Twentyfirst Century (Carnegie Council on Adolescent Development 1989, 43) encourages middle-grade teachers “to promote a spirit of inquiry and to stimulate students to think about and communicate ideas.”