Facts101 is your complete guide to A Friendly Introduction to Number Theory. In this book, you will learn topics such as Pythagorean Triples and the Unit Circle, Sums of Higher Powers and Fermat's Last Theorem, Divisibility and the Greatest Common Divisor, and Linear Equations and the Greatest Common Divisor plus much more. With key features such as key terms, people and places, Facts101 gives you all the information you need to prepare for your next exam. Our practice tests are specific to the textbook and we have designed tools to make the most of your limited study time.