Understanding how to intensify an intervention is critical to implementing response-to-intervention (RtI), a tiered, problem-solving framework to deliver evidence-based interventions per student needs. Research and practice guidelines provide conflicting recommendations for delivering math interventions (i.e., treatment intensity) within RtI. The present study used an adapted alternating treatment design to examine the impact of varying the session length, or number of minutes per intervention session, on student outcomes (i.e., digits correct per min, DCPM). Four female first-grade students identified in the frustrational range (i.e., less than 14 DCPM) for subtraction computation received a packaged intervention (i.e., Cover-Copy-Compare and Schema-Based Word Problem Instruction). The math intervention during the shortest (i.e., 10-min) session length led to similar improvements compared to two of the recommended session length conditions (i.e., 20-40 min) for three out of four students. Following the 5-week intervention, all four students reached an instructional level (i.e., 14-31 DCPM) for the intervention targets, similarly, across all three session length conditions. Implications for research on treatment intensity, math interventions, and RtI are discussed.