The effects of a fluency building math program on addition and subtraction computational skills were evaluated using a multiple probe across subjects design. Two students with developmental disabilities and one student with attentional difficulties participated in a supplemental intervention using the Great Leaps Math program. Analyses indicated all three students made gains in oral fluency of math facts, and one student made progress in written fluency and written fluency generalization as well. Results are discussed within the context of differential rates of student progress, graphing student progress, and changes in student academic and social behavior with implications for practice and future research. (Contains 1 figure.)