The Math You Need, When You Need It (TMYN) is a set of online tutorials designed to help students develop and review mathematical skills that are applied in undergraduate geoscience courses. We present results of a three-year study of more than 4000 students in 106 geoscience courses at a variety of post-secondary schools who were assigned TMYN tutorials as supplemental mathematics instruction. Changes in student scores from preto post-test suggest that the support provided by programs such as TMYN can begin to reduce the gap between mathematically well-prepared and underprepared students; in essence, TMYN levels the quantitative playing field for all geoscience students. On average, both highand low-performing students who fully participated in the use of TMYN as a part of their course showed learning gains, although gains were larger for students who performed poorly on the pre-test. Our findings emphasize the conclusion that students who interact with context-specific quantitative problems can potentially improve their mathematical skills, regardless of initial level of mathematical preparation. We suggest that this type of support could generalize to other science courses.