As part of the TV Ontario Telidon and Education Field Trials, a study was made of the application of the Telidon videotex systems to computer-assisted learning (CAL), including the future directions of these applications and differences in achievement between advanced and general-level students. Subjects were 129 middle- to upper-middle, ninth-year mathematics students in Burlington (Ontario), who used a CAL module based on the general mathematics course outlined by the Ontario Ministry of Education. Within the student sample were two control and two experimental groups, one of each in the general level and advanced level programs. Control groups received a lesson on the transformational geometry topic of dilatations through a traditional socratic method and chalkboard presentation, while the experimental groups used an individually paced module presented on the video screen. Posttest results showed little difference (2%) in achievement for the two control groups. In the experimental groups, the advanced level group was significantly superior (15%) to the general level. The teacher-led group in the general level did 12% better than the Telidon group, while the advanced level Telidon group performed 1% better on the average than the teacher-led group. (Author/LMM)