This study from 2019 investigates whether the impact on a STEM teacher's evidence-informed teaching approach using the evidence of flipping the classroom research improves students' (13-14 years old) motivation in a Dutch setting and if this approach allows students to perform better. We report this approach in line with the cycle of expansive learning of Engeström. We asked: "To what extent can evidence based on the flipping the classroom approach improve the motivation and results of grade 8 preuniversity track students doing mathematics?", followed by the subquestions: "To what extent does education by the FtCA increase student motivation?" and "To what extent does education by the FtCA ensure better test results for students?". A questionnaire is used to investigate to what extent the motivation of students increased, and a teacher is interviewed about his experiences with the "flipping the classroom" model. To test whether the results have improved, a pre- and post-test is taken and analyzed. A significant increase in both intrinsic and extrinsic motivation has been found, and students gained a stronger sense of autonomy, competence, and belonging. The test results improved, but the difference is not statistically significant. However, despite the disappointing test results, the teacher was very positive about the new way of working.