This bulletin provides States and local school systems with information on recent efforts to improve elementary school mathematics instruction, fulfilling a need for a single source in which factual descriptions of the major experimental projects and other improvement procedures are brought together for study. It does not attempt to evaluate individual projects; however, some guidelines for decision-making are suggested. The bulletin contents describe: (1) Why there is an increased emphasis on mathematics; (2) What changes are taking place; (3) How mathematics is taught; (4) Selected experimental projects--School Mathematics Study Group Program, Greater Cleveland Mathematics Program, University of Illinois Arithmetic Project, Madison Project, Stanford Project, and Minnesota Elementary Curriculum Project; (5) Other improvement procedures; and (6) Implications for elementary school personnel. Appended are a selected bibliography, a flow chart of basic mathematical ideas, and a partial list of publishers of commercial arithmetic textbooks. (Contains 44 footnotes.) [Best copy available has been provided.]