School Mathematics continues to present challenges for students at all levels of the educational system. In many mathematics classrooms, learners are not provided with opportunities to be actively engaged with the subject matter. The curriculum strategies that are employed present mathematics in a de-contextualized manner without any applications to real-world scenarios.

By using a mixed-methods research methodology, this study explored solving differential equations in the learning of Calculus using the Realistic Mathematics Education (RME) approach. The research employed both qualitative and quantitative approaches with an instructional action research design.

Twelve in-service teachers who were pursuing the Bachelor of Education degree in mathematics education participated in the research. They completed a questionnaire with items that required free responses on their experiences in doing Calculus using the RME approach and they did the summative assessment worksheets. For comparative analysis, the participants were required to complete two assessment worksheets on Calculus. The data were analysed using qualitative data coding analysis for themes and paired t-test.

The findings indicate that there is no significant difference in in-service teachers’ performance when they learn Calculus in a contextualized context. In addition, further findings indicate that in-service teachers have mixed opinions about their experiences learning Calculus when the RME approach is used. RME is an instructional approach that can have several positive outcomes on students’ experiences and learning, and can therefore be applied to all levels of the educational system for the teaching and learning of mathematics.