Poor achievement on standardized math tests negatively impacts high school graduation rates. The purpose of this quantitative study was to investigate if math instruction in business classes could improve student achievement in math. As supported by constructivist theory, the students in this study were encouraged to use prior knowledge and experiences to make new connections between math concepts and business applications. The key research question examined if there was a significant increase in the standardized mathematics test scores of students enrolled in business classes with extended mathematics instruction compared to the standardized test scores of students not enrolled in business classes with extended mathematics instruction. The 2-sample t-test was used to compare the scores of 42 students in the treatment group to the scores of 47 students in the control group. Based on the findings, there was not a significant difference in the scores of the treatment and control groups. Recommendations for future research included redesigning the treatment to involve additional areas of mathematics instruction as well as extending the number of weeks for the treatment. This study may effect social change by informing teachers and administrators at the local site of the need to examine the effects of incorporating math into other content areas and recommending continued research in this area. The additional exposure, practice, and learning opportunities in math may help high school students achieve in mathematics and ultimately improve graduation rates.