Students struggling with mathematics may benefit from early interventions aimed at improving their mathematics ability and ultimately preventing subsequent failure. This guide provides eight specific recommendations intended to help teachers, principals, and school administrators use Response to Intervention (RtI) to identify students who need assistance in mathematics and to address the needs of these students through focused interventions. The guide provides suggestions on how to carry out each recommendation and explains how educators can overcome potential roadblocks to implementing the recommendations. Each recommendation is rated strong, moderate, or low based on the strength of the research evidence for the respective recommendation. Specific recommendations include: (1) Screen all students to identify those at risk for potential mathematics difficulties and provide interventions to students identified as at risk; (2) Committee-selected instructional materials for students receiving interventions should focus intensely on in-depth treatment of whole numbers in kindergarten through grade 5 and on rational numbers in grades 4 through 8; (3) Instruction during intervention should be explicit and systematic, and should include models of proficient problem solving, verbalization of thought processes, guided practice, corrective feedback, and frequent cumulative review; (4) Interventions should include instruction on solving word problems that is based on common underlying structures; (5) Intervention materials should include opportunities for students to work with visual representations of mathematical ideas and interventionists should be proficient in the use of visual representations of mathematical ideas; (6) Interventions at all grade levels should devote about 10 minutes in each session to building fluent retrieval of basic arithmetic facts; (7) Monitor the progress of students receiving supplemental instruction and other students who are at risk; and (8) Include motivational strategies in tier 2 and tier 3 interventions. Four appendixes are included: (1) Postscript from the Institute of Education Sciences; (2) About the authors; (3) Disclosure of potential conflicts of interest; and (4) Technical information on the studies. A glossary is included. (Contains 314 footnotes, 12 examples and 7 tables.)