Investigated was the mathematics achievement of several hundred junior high school students, believed by their counselors and teachers to be "slow learners." This investigation focused on two critical problems: (1) whether some children benefit from less rapid pacing of material, and (2) which are the strongest predictors of achievement in junior high school mathematics for those labelled "slow learners." It was anticipated that the group of slow learners, 25th to 50th percentile band, would be able to complete in two years material which would be approximately equivalent to the mathematics studied by the control group in one year. The seventh grade youngsters studied the School Mathematics Study Group "Introduction to Secondary School Mathematics" and the ninth grade studied the School Mathematics Study Group "Introduction to Algebra." The resulting statistics of the present study have indicated if the school's classification of the "slow learner" is used, these students show a greater gain in achievement in the "new" mathematics, when a "modified modern" text is studied, and when the pace of instruction is less rapid. (RP)