To determine the effect of learning computer programming and the use of a computer on mathematical achievement of eleventh grade students, for each of two years, average and above average students were randomly assigned to an experimental and control group. The experimental group wrote computer programs and used the output from the computer in their mathematics class. Course material included quadratic functions, complex numbers, linear systems sequences, series and limits, and trigonometry. Pre- and post-test measures were taken on these topics. Findings yielded (1) significant differences favoring the experimental group for measures of achievement in algebra and quadratic functions; (2) significant differences in trigonometry achievement favoring the control group; and (3) computer use appears to contribute most to learning of complex processes, organization and relation of data, and infinite processes. (Author/JG)