The study investigated whether the pre-arrangement of math facts in spaced repetitions redundancy would increase the acquisition rate of a second grader with poor mathematics achievement. Baseline data were provided by observation of in-class math performance of addition sums zero through 18. In the experimental phase, worksheet problems were presented visually and arranged in 50% spaced redundancy and the subject was reinforced for correct responses. Subsequent intervention phases used only reinforcement and spaced redundancy and then only spaced redundancy. During the intervention phases, the S's error rate dropped to near zero, with long term retentive learning demonstrated. Results suggested that 50% spaced redundancy was a powerful antecedent stimulus in remediating math deficiencies. (CL)