This research is based on the assumption that the use of learning media can help students' understanding at the concrete operational development stage. Among them is the stamp game media which is one of the mathematics learning media. In this research, an experimental design was used with a quasi-experimental time series design. The research results show that students' initial abilities are still quite low. After intervention was carried out through the use of the stamp game learning media, there was a difference in the average student test results. The results of the Wilcoxon signed ranks test obtained a z value of -2.271 and an asymp value of sig. smaller than the alpha level of 5% (0.05) so it rejects Ho. The conclusion of this research is that the use of the stamp game as an intervention medium provides an increase in the multilevel addition ability of children with mild intellectual disabilities in Malang City Special Schools.
Pradipta et al. (Sun,) studied this question.