Although brief experimental analysis (BEA) procedures have been effective for aiding instructional decision making in the area of reading, there is a paucity of research extending this technology to mathematics. This study extends the literature on mathematics BEA by using an abridged data series that compares skill- and performance-based interventions, and examines effects of the selected intervention across time and on generalization worksheets. Brief experimental analysis and extended analyses across target and generalization worksheets were conducted with four children in grades 3 to 6. Results demonstrated that mathematics BEA can be used to select effective interventions and that these results remain stable across time and compared to baseline. However, collateral effects on generalization materials were found for only 1 of 4 children. (Contains 1 table and 3 figures.)