The educational literature emphasizes the key role of analytical thinking (AT) and applied mathematical skills (AMS) in solving engineering prob-lems and calls to nurture these skills in school STEM education. This study proposes and explores a strategy for fostering AT and AMS among middle school students and prospective teachers through practice in digital design and 3D printing. The study involved 32 seventh grade students and five prospective teachers of technology. Both groups learned a 10-hour work-shop, “Make a spinning-top.” The participants designed spinning-tops that can fit into a Kinder Surprise egg and analysed their geometric and mechani-cal properties. We collected data from students’ worksheets, their designed artefacts, and in-class discussions. The results indicated that the assignment prompted the participants to apply AT and AMS. School students designed complex models, inquired into their geometry, and verified their designs through 3D printing. The worksheets were found to be an effective tool to frame and guide students’ thinking in the design tasks and the creation and testing of mathematical models. For the prospective teachers, the workshop, accompanied by lectures on the methodology of experiential learning, ena-bled to implement mathematical solutions in designs and develop instruc-tional units on the subject.