Mathematics is the queen of science, but many students struggle with this subject as slow learners. Slow learners can accomplish their full potentials with an appropriate learning approach. In this study, these slow learners were examined using Realistic Mathematics Education approach. Single subject research was employed in this study, with multiple baseline cross-conditional designs at home and in the classroom. For data analysis, an internal analysis approach and an analysis between curves of both conditions were conducted. The results revealed that slow learners had a higher tendency to perform better when studying at home compared to in class. In addition, after receiving, slow learners' score improved, but when being situated in another condition, the increase in score slowed or stagnated. The implication is that in order to optimize slow learners' learning potentials, teachers instruct them using the MRE approach at school based on home settings.