Math Trailblazers® 4th Edition is a coherent, research-based, K–5 mathematics curriculum that reflects the goals and ideas of the National Council of Teachers of Mathematics (NCTM) Principles and Standards for School Mathematics and aligns with the Common Core State Standards. Math Trailblazers is an elegantly engineered, inquiry-based curriculum that makes mathematics engaging and meaningful to students. Math Trailblazers is based on more than 25 years of National Science Foundation funded research by experts at the Teaching Integrated Mathematics and Science (TIMS) Project and the Learning Sciences Research Institute of the University of Illinois at Chicago. Math Trailblazers remains a comprehensive and rigorous curriculum rich in hands-on activities, lively discussion, and cooperative opportunities for learning. This edition in particular is designed to focus on teacher as learner so that all classrooms are mathematically confident.