The National Council of Teachers of Mathematics (NCTM) Vision for School Mathematics invites us to "Imagine a classroom, a school, or a school district where all students have access to high-quality, engaging mathematics instruction." Our goal in writing this book is to provide examples of how a symbolic geometry system, Geometry Expressions, can begin to make this happen. Geometry Expressions provides a playground where students can discover their own mathematics. They will begin to see mathematics as something that is created, not just a set of facts made up long ago. Once students take...