This study investigated the effect of systematic early numeracy skill instruction on grade-aligned 4th and 5th grade Common Core math skill acquisition for three 4th and 5th grade students with a significant intellectual disability. Students were taught early numeracy skills (e.g., number identification, making sets to five items, simple addition) using theme based lessons, systematic prompting and feedback, manipulatives and graphic organizers. Four Common Core math standards were task-analyzed to identify the early numeracy skills needed to access the standard. A multiple probe across students design was used to examine the effects of the early numeracy instruction on the number of steps completed on each of the grade-aligned math standards task-analysis. Results indicated a functional relationship between the early numeracy skill instruction and students independent correct responses on grade-aligned math. Implications for practice and future research are discussed.