A huge mountain in sight - or better step by step? This is how the author introduces the planning and execution of the first lessons, systematically connecting them with more complex topics up to the examination level. The selection of chapters is based on surveys of trainee teachers, ensuring a strong practical relevance. Classic training areas (lesson planning, reflection, methods, performance assessment, teacher presentations, etc.) are complemented by current topics such as differentiation, diagnosis, inclusion, and language support. This practical book is aimed at education students, trainees, and beginners in the subject of mathematics in secondary levels I and II, and serves primarily as a helpful guide for the teacher training period.