Recent multiplication with regrouping research shows that the combination of the concrete-representational-abstract (CRA) sequence and the Strategic Instruction Model (SIM) has been effective in several studies. More evidence is needed to demonstrate CRA-SIM's effectiveness across settings and students. Therefore, the purpose of this study was to replicate previous findings in which CRA-SIM led to improved performance of students receiving tertiary interventions. This study extended the research by including problem-solving application in order to align the intervention with current standards for mathematics. Three elementary students receiving tertiary interventions participated in the study. The researchers used a multiple baseline across students design to show a functional relation between CRA-SIM and student performance. In addition to mastery of multiplication with regrouping, students applied their knowledge, discriminating between different operations when solving word problems. The implications and program components that influenced these results will be discussed.