At the heart of most probability theory problems lies a calculation from the vast and often confusing field of permutations and combinations.
This book aims to give you a strong theoretical background in the field: you will learn more about how to count the number of arrangements of common objects than you ever thought possible.
I am a firm believer in the power of learning by doing: to this end, I have ensured that this book is full of solved problems and of exercises that you can try by yourself, so that your accuracy and speed will both improve by the time you complete even a fraction of the book.
Make sure that you spend extra time on the problems that you are unable to solve: understanding where you went wrong is a step that is essential to self improvement.
For some, the level of arithmetic manipulation involved will be time consuming. In such cases, I encourage you to use a calculator; the aim of this book is to teach you what to calculate, rather than to become a mental mathematics whiz in a short period of time.
Welcome to the fascinating world of permutations, combinations, and factorials!