Patterns and visualization are critical areas for developing conceptual understanding of mathematics across K-12. Building on elementary school students’ experiences with manipulatives and visual models, middle school teachers can extend the use of concrete and visual representations to connect fractions, ratios, proportions, linear relationships, and functions. Workshop participants will explore developmental trajectories related to the big ideas of pre-algebraic and algebraic thinking through the use of manipulatives and diagrams (e.g., pattern tasks, area models, Algebra Tiles). Come join us in developing a deeper understanding of patterns and visualization in mathematics.