Information about the series edition: The concept of "Mathefreunde" ensures the successful development of fundamental mathematical competencies in all children. The teaching material consistently employs methods of differentiation, independent work with the help of self-assessment, and reinforcement through practice, repetition, and application. The components of "Mathefreunde" comprehensively cover the learning areas of arithmetic, geometry, and measurement. Practical problem-solving is a constant element. Additionally, content on combinatorics and data, frequency, and probability has been included. "Mathefreunde" demonstrates many additional strengths: Differentiation: All tasks are divided into three levels of differentiation, which are immediately recognizable. Review tasks: These serve to reinforce the material and prepare for new learning content. Self-assessment: Solution numbers and solution words.