Schools are having to find innovative ways to increase the instructional time in the school day to not only address deficiencies in students’ mathematical knowledge but to also increase the academic rigor and prepare students for college and careers. The most popular approach is double-dosing, where students give up an elective class in order to take an additional mathematics class. Whereas this is a popular approach, there have not been very many studies on the effectiveness of this practice. This study adds to the body of knowledge on double-dosing by analyzing the effectiveness of the support class through student achievement on the state End of Course Coordinate Algebra test as well as through Student Growth Percentiles. Analysis of Covariance (ANCOVA) was used for all analyses. Criterion-Referenced Competency Test scores were used as the covariate. The participants in this study were first-time freshmen enrolled in Coordinate Algebra in an urban district of approximately 25,000 total students. Data indicated that the interaction between support classes and school year were trending toward significance for both the End of Course scores (p = .056) as well as Student Growth Percentiles (p = .068). In the second year of the study, students enrolled in the Mathematics Support class scored higher on the End of Course test and had higher Student Growth Percentiles. Additionally, there was a significant main effect for support class on the Student Growth Percentiles (p = .028). Students in the support class did achieve significantly higher growth than students who were not concurrently enrolled in the support class. Whereas increases in mathematical growth do not necessarily result in increases in achievement scores, as evidenced by the data in this study, the Mathematics Support classes are effective in increasing student learning in mathematics.