Presented is a report on a Research and Development program in the use of computer-assisted instruction to teach mathematics in grades 4 through 6. Approximately 60 computer terminals of the PLATO type were installed in elementary school classrooms, 4 terminals per classroom. Each student received one-half hour of mathematics lessons, via computer, each school day, plus whatever instruction the teachers chose to provide. The CAI in question was not the usual sort, using frame-by-frame presentations of content via natural language instruction. Instead, it was based upon the Madison Project strategy of paradigmatic learning experiences, and was presented to students via a computer system having a good audio-visual interface between computer and child. Several independent third-party evaluations of the computer-based curriculum have been carried out. These evaluations indicate positive results for the curriculum in terms of achievement and attitude. (Author/MK)