It is increasingly important for mathematics students to engage in active learning along with discussion of material with their peers. "Slopes" is a mobile application designed to visualize solutions to differential equations and support active learning in the classroom. We implemented group activities using "Slopes" into an ordinary differential equations class, conducted observations and focus groups, and examined final poster projects to determine the benefits of the app. We found that students used "Slopes" to visualize solutions, aid in discussion and cooperation, and demonstrate understanding of differential equations concepts.