Block by Block to Success: Teaching Subtraction With Regrouping to High School Students With Intellectual Disabilities Through a Manipulative‐Supported Direct Instruction Package

ABSTRACT This study examined the effectiveness of the manipulative‐supported direct instruction package for teaching three‐digit subtraction with regrouping to high school students with intellectual disabilities. In addition to examining acquisition, the study evaluated whether accurate responding occurred after the removal of the manipulatives, whether performance was maintained over extended follow‐up intervals, whether responding was generalized to computer‐presented subtraction problems, and teachers' evaluations of the intervention's goals, procedures, and outcomes. This study employed a multiple‐probe design across participants. The current study included four high school students, aged 15–17 years, diagnosed with mild intellectual disabilities and enrolled in a special education vocational school. Findings indicated that three participants acquired the target behavior, achieving 80% or higher accuracy, maintained it for 4–12 weeks after instruction, and generalized it to computer‐based tasks without manipulatives. Teachers provided positive feedback on the study's purpose, the acceptability of the intervention, and the significance of the results. The study contributes to the limited research on high school students and supports the integration of effective instructional practices into real‐world classrooms. Implications for future research include exploring the combined use of physical and virtual manipulatives, broader measures of generalization, and contextual influences on learning outcomes.