The aim of this study was to investigate the effect of a precision teaching (PT) framework on the mathematical ability of students with intellectual and developmental disabilities. We also examined if students of moderate mathematical ability could perform as well as their peers with fewer difficulties with their math skills. Sixteen students participated and were divided into three groups. One group engaged in PT, and the other two groups functioned as comparisons. The PT group practiced six skills introduced linearly. An A-B design was used for the five component skills, and a multiple baseline across participants design was used for the composite skill (addition). The intervention led to a significant improvement in all skills, including addition, and this was associated with a large effect size; student performance met or exceeded that of their peers. Overall, the findings suggest that PT is an efficient and effective approach for teaching students with IDDs.