The purpose of this action research was to determine the level of improvement of middle school students who were low performers in a mathematics class (N = 8) and who received "explicit instruction" with "double dosing" compared to their peer group who received normal instruction (N = 49). Results showed that at-risk participants: (a) demonstrated large increases in noncalculator and calculator performance, (b) performed near their peer group on the posttest assessments, and (c) performed at or near their peer group across the four quizzes. Implications for future research are discussed. (Contains 1 figure and 2 tables.)