DOUBLES . Doubles is a key strategy that helps students build strong number sense and develop fluency with addition and subtraction. Doubles facts (like 4 4 or 7 7) provide an efficient way for students to solve problems quickly and accurately, and they form the foundation for related strategies such as near doubles (e.g. 6 7). . When students are confident with their doubles, they can draw on these known facts to solve more complex problems, reason mathematically, and work flexibly with numbers