For years, students have been taught to cross multiply when presented with proportion problems. Few understood what they were doing or why they were doing it. Rarely were students invited to think about various representations to determine the relationship between the two ratios being compared. The ideas and activities in this guide will help you provide students with the conceptual understanding of ratios and proportional thinking that is essential for solving real-world problems and achieving success in higher-level mathematics.
It's All Relative includes thirty modules, which are aligned to specific Common Core State Standards. Each module in this accessible, spiral-bound flipchart addresses specific mathematical practices and common misconceptions; features timely classroom examples; includes proven, ready-to-use activities; and provides ideas for adapting activities to meet the needs of individual learners. The authors particularly emphasize how to use visual models-tables, tape diagrams, graphs, and double number lines-to represent ratios and proportional thinking. These visual models, which may be new to many teachers, enhance students' conceptual understanding and improve their ability to solve a wide range of proportional reasoning problems.

Anne Collins is the director of the mathematics program at Lesley University. She has been providing mathematics content professional development institutes and courses for teachers for the past fifteen years and recently served on the NCTM Board of Directors (2010-2013). Linda Dacey, professor of mathematics and education at Lesley University, works with preservice and in-service teachers, helping them to develop both their content knowledge and their practice. Her research focuses on problem solving, number sense, and strategies for differentiation.