The thoroughly revised new edition combines new methodological-didactic approaches to fundamental mathematical content with proven and newly designed tasks from practice. This aims to guide and empower students to work independently and responsibly, enabling them to meet the demands of an ever-changing work environment. A focus of this book is on real-life tasks and questions that can also be solved using modern technologies such as the Internet and spreadsheets. Teachers will find worked-out introductory tasks at the beginning of new chapters, along with a wealth of didactic tips and explanations. The practice exercises are designed to address as many mathematical competencies as possible. Modeling, interpreting, and reasoning are promoted in the spirit of mathematics.