Concept: The goal is to convey and acquire fundamental, application-ready knowledge as well as to develop secure calculation skills. The content is systematically expanded and deepened according to the spiral principle. A high degree of visualization, linking existing knowledge with new learning material, action patterns, and various solution paths actively promote discovery-based learning. The development of thinking and learning strategies, along with a comprehensive range of exercises, helps learners to internalize and apply the knowledge. In selecting tasks, particular attention was paid to ensuring that calculation methods are sufficiently reinforced and that tasks can be solved through hands-on activities. Tasks with varying levels of difficulty on the same content allow for differentiated approaches. Productive practice is encouraged through prompts for commentary.