Project Special Elementary Education for the Disadvantaged (Project SEED) is a nationwide program in which mathematicians and scientists from academia and industry teach abstract, conceptually oriented mathematics to full-sized classes of elementary school students as a supplement to their regular arithmetic classes. A Socratic group-discovery format is used. In its implementation in the Dallas (Texas) public schools, SEED was used with all levels of children in schools with high percentages of minority and low-income children. The 1989-90 evaluation considered the program's impact on the achievement of more than 3,000 students who had one, two, or three semesters of SEED instruction in grades four through six. The achievement these students attained was compared, using longitudinal information where possible, with that of non-SEED students through the use of Iowa Tests of Basic Skills scores and other measures. Impact of one, two, and three semesters was apparent, with the minimum at 2.2 months (1 semester, in problem solving) and the maximum at 9.0 months (computation, after 3 semesters). Project SEED students were also more likely to enroll in advanced mathematics in secondary school. Evaluators recommend that the program be expanded to as many students as possible. Thirteen tables present evaluation findings, and two appendixes contain an additional 13 tables of findings from prior program evaluations. (SLD)