Percentage calculation at lower secondary level

Authentic, socially relevant contexts and data are becoming increasingly important in mathematics education. The goal is not only to provide students with mathematical competencies but also to empower them for responsible citizenship in the sense of sustainable development. This work focuses on percentage calculation as a mathematical topic that has been didactically prepared in connection with the 17 Sustainable Development Goals (SDGs) established by the United Nations (UN) in 2015. Based on subject-specific didactic findings on percentage calculation, technological foundations, and educational theoretical concepts, a learning path for the 7th grade was developed and implemented fully digitally via GeoGebra Classroom. The implementation took place in a class at a middle school in South Tyrol within the framework of the Design-Based Research approach. In this process, the digital learning environment enabled a detailed analysis of the subject-specific and interdisciplinary learning objectives.