Virtual manipulatives are an emerging intervention to support students with disabilities in mathematics. Through a multiple probe across participants design, researchers examined use of an intervention package consisting of a virtual manipulative (i.e., the Two-Color Counter app-based manipulative) and the system of least prompts (SLP) to support students' acquisition, maintenance, and generalization of solving addition of integers problems. Researchers found a functional relation between the intervention package and middle school students' accuracy. All three students acquired the skill, with two able to consistently generalize as well as maintain adding integers. The three students were also generally independent when solving the problems with the app.