Mathematics instruction for students with intellectual disabilities and autism is important. However, it is imperative for researchers and practitioners to focus on the maintenance of mathematical concepts and not just acquisition for these students. Through a single-case multiple probe across participants study, researchers explored an intervention package consisting of a manipulative-based instructional sequence involving virtual manipulatives and then representations (i.e., drawings; referred to as the virtual-representational instructional sequence), explicit instruction, the system of least prompts, overlearning, and support fading to support students with intellectual disability and autism to acquire and maintain multiplication or division skills. The three middle school students who completed the entire intervention acquired and maintained their targeted mathematics skill--in multiplication or division. The results have implications for use of intervention packages to teach foundational mathematics skills to students with developmental disabilities.