The goal of this book is to assist teachers (current and future) in developing the pedagogical knowledge of mathematical topics as they evolved over time, with respect to the mathematics found in middle school curricula. The proposed book explores the key concepts of the mathematics of middle school through their historical development. History becomes a means to understanding and connecting mathematical concepts at a level that is relevant to teaching middle school students. The historical approaches from mathematics around the world are investigated with the aim to build conceptual and procedural understanding of mathematics taught in intermediate Grades. Teaching approaches based on the history of the concepts are presented. Relevant historical facts/anecdotes/problems are included for use in mathematics classrooms.