This study examines students’ perceptions of the subjects geography, mathematics, and computer science in integrated science, technology, engineering, and mathematics (STEM) lessons. Although the importance of an integrated approach in STEM education is emphasized, researchers are not clear about whether students perceive connections between the subjects on the one hand and subject-specific working methods and content in integrated lessons on the other. Data was collected in an integrated teaching unit on the sustainability of apples using an open-ended digital questionnaire in to two ninth grade classes in Hamburg, Germany (n = 38); this data was analyzed using qualitative content analysis. The results reveal that students perceive the subjects differently, but similarities can also be identified. While subject-specific content is perceived—such as the use of maps in geography, the calculation of volumes in mathematics, and Dijkstra’s algorithm in computer science—methodological connections, such as calculating, analyzing diagrams, or solving problems, are anchored across disciplines. This suggests that the subject-specific contents are not lost in integrating lessons, and that connections among the subjects are, to a certain extent, promoted.

Integrated teaching encourages students to think across disciplines and view key human issues from various perspectives. Although mathematics and geography are taught as separate subjects in schools, they frequently intersect in real-world issues, with scientific problems often analyzed using mathematical methods. The purpose of this article is to systematically review the understanding of study characteristics, teaching content, and forms of integration between geography and mathematics. A systematic review of 26 studies was conducted in accordance with PRISMA guidelines, involving searches of four databases from 2000 to 2023. Screening and selection were performed independently by two researchers. Data were analyzed via structured qualitative content analysis. This systematic review demonstrates that integrated teaching can improve knowledge and skills of students compared to segregated teaching. The findings reveal that contents such as Education for Sustainable Development, cartography, and astronomy and space travel are the main topics covered in subject-integrated mathematics and geography lessons. The study also highlights gaps, especially in long-term effects and teacher involvement in quantitative research.