This brief from the Learning Policy Institute shows that U.S. students often struggle with math. After repeated negative experiences, too many come to believe they are “not a math person” and withdraw from math learning. This problem predated COVID-19, although the acute impacts and lingering effects of school closures have made the need for change impossible to ignore. The research finds that classroom learning environments strongly influence student math outcomes, particularly for students of color and those from low-income families. Instructional quality matters greatly, but evidence also shows that students’ classroom relationships, sense of belonging, and mindset toward learning shape their math outcomes. Drawing on case studies of 10 middle school math teachers across five California schools, this brief illustrates how teachers cultivated these research-aligned conditions for learning in their math classrooms. It also identifies implications for teachers and the instructional coaches and leaders who support them.