TERC will develop a comprehensive mathematics curriculum for grades K-6 based on investigations in number, data, and space, and emphasizing depth and understanding. The curriculum will stress mathematics as a pattern-finding science, make the discipline more accessible to both students and teachers, and build teachers' knowledge of how students learn mathematics. TERC will design, evaluate, and disseminate ten curriculum modules for each grade level. Each module will focus on a set of related and developmentally appropriate investigations which introduce key mathematical content within a compelling context. The teaching built into the print materials (through scenarios depicting analytic work in classrooms), and into videotapes of effective mathematics teaching in action. Evaluation of the project will include formative research, as well as an examination of the impact of the curriculum on students and teachers. Investigations will be disseminated through publications aimed specifically at elementary school educators. The curriculum will be published by Dale Seymour Publications, who has made a major financial commitment to the project.