Regular practice and systematic foundational training ensure that mathematical competencies are built and secured in the long term. Warm-ups as lesson starters play an important role in this process. In this volume, you will find 63 developed warm-ups for your teaching, which will help you reinforce mathematical foundations with your students. Each warm-up consists of two to three short tasks covering all areas of learning on a single page. A clear table of contents makes it easy to find the desired mathematical content. An icon on each page classifies the warm-ups as easy, medium, or difficult, allowing you to choose the appropriate warm-up based on your students' skill levels. On the right side of each copy template, you will find the printed solutions—simply cover them when copying or using an overhead projector.