Sidwell Friends’ math program is designed to build fluent mathematicians, skilled problem solvers, and creative thinkers. The goal of the program is to help students construct their own mathematical knowledge. In the Lower School, students learn not only how to use algorithms, but how to think mathematically and tackle authentic, real-world math problems. The math classrooms encourage risk-taking, sense-making, curiosity, and wonder. Teachers and students alike explicitly cultivate growth mind-sets. Teachers introduce new concepts in ways that allow children to move from the concrete to the pictorial to the abstract. In addition to building skills and fluency, the program focuses on developing mathematical habits of mind: perseverance, precision, reasoning, and logic. All grades (K–6) use the Illustrative Mathematics program, and teachers use ongoing assessments to differentiate and drive instruction.