In this study, we focused on nine fifth-grade students from Dong’ao Elementary School in Yilan County, integrating robotics technology and the indigenous cultural context of a “banquet” into mathematics to design and teach a Science, Technology, Engineering, Mathematics (STEM) interdisciplinary course on the concept of quantitative relationships. The teaching strategy of collaborative problem solving (CPS) was adopted. The teacher first explained the concept of quantitative relationships using presentations, teaching aids, and digital interactive materials, followed by introducing the functionality of robots. Using the example of a “banquet reception,” students were encouraged to use their imagination to program the robots to perform movements, rotations, facial expressions, sounds, and gestures, completing various learning tasks related to quantitative relationships. The results showed a significant improvement of 32 points in post-test scores compared with pre-test scores. The math test included three question sets with a total of 10 questions, with a full score of 100. The science imagination test, designed around the banquet reception scenario, consisted of two main tasks with four questions in total, with a full score of 18 and an average score of 13.1. On the basis of the levels of scientific imagination required, students found tasks requiring “imagination” and “association” easier than those involving “fantasy” and “innovation.” Students were able to propose more than two or three possible problems, impacts, and solutions. This study involved the use of various digital tools in interdisciplinary course activities. It is essential to check the equipment and network before each class to ensure a smooth teaching process.