The 2Partner Small Group Lesson Curriculum, or 2PSG, is a supplementary mathematics curriculum designed to provide either a preview or review of important mathematics concepts so that students can benefit more fully from Tier 1, core mathematics instruction. The 2PSG Lessons are intentionally designed to support both student and teacher learning. These lessons engage students and teachers in conceptual mathematics through the use of manipulatives, models, and visuals to support effective delivery by a range of educators, including classroom teachers, interventionists, tutors, or support persons.