Recent years have seen a quick expansion of tablet computers in households and schools. One of the educational affordances of tablet computers is using math apps to engage students in mathematics learning. However, given the short history of the mobile devices, little research exists on the effectiveness of math apps, particularly for struggling students. To fill in the gap, an exploratory study was conducted in an inclusive fourth grade classroom, in which about half of the students were either at-risk or had disabilities. The students used three math apps that employed different scaffolding strategies to support learning of decimals and multiplication. Pre- and post-tests showed that use of the math apps improved student learning in mathematics and reduced the achievement gap between struggling students and typical students. More studies should be conducted to identify effective math apps.