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Please familiarise yourself with the structure of this book. It is divided into 4 chapters, each of which consists of paragraphs. In total, the textbook contains 47 paragraphs, each of which begins with a presentation of theoretical material. When studying it, pay special attention to the text printed in a different font. This is how the book highlights the words that mean mathematical terms, rules, and the most important mathematical statements. Usually, the presentation of theoretical material ends with examples of solving problems. They can be considered as one of the possible examples of how to write a solution.

Each chapter is accompanied by problems for independent solving, which you should start only after you have mastered the theoretical material. The tasks include both simple and medium difficulty exercises and difficult tasks (including those marked with an asterisk (*)).

Each chapter ends with a special task, which we called the "Task from the Wise Owl". To solve it, you will need to be resourceful and smart. The "When the Lessons Are Done" section will help you deepen your knowledge of important mathematical objects such as numbers and shapes. We hope you will find it interesting.