Teaching mathematics is one of the most difficult and important jobs that anyone can do. Mathematics is a critical part of education and an essential building block for problem solving skills that are needed in the real world. However, many students struggle to learn and understand mathematical concepts and educators need to do everything possible to help our students learn. This book focuses on four areas necessary to be an impactful teacher of mathematics: Planning, Pedagogy, Assessment, and Relationships. For each of the ideas presented in the book, a brief introduction will be shared and then two different perspectives will be detailed with examples. The first is Not like This which is often the traditional way of teaching mathematics or the less effective approach. The second perspective is Teach Like This which is my recommended approach based upon research and my own experience as a teacher, math coordinator, and graduate instructor of math education.