This book is different from other books of similar content, not in term of the material it contains but in term of the way this material is processed and presented. It does not only study the arithmetic topics studied in school, but also analyzes how these ones can be used in various other areas and in solving real life problems. Additionally, it does not try to turn enjoyable and entertaining problems into tedious tasks that are often fruitless for serious work. It avoids difficult problems and selects only the material that is accessible for the majority of the readers.