This study aimed to explore the subjective experiences of a mathematics teacher at SMPN 9 Jayapura in implementing the GASING (Gampang, Asyik, dan Menyenangkan) learning method using a qualitative phenomenological approach. The main problem underlying the application of this method was the students' difficulty in understanding abstractly taught mathematical concepts and their low basic numeracy skills, such as multiplication and division. Data were collected through in-depth interviews with a teacher who had practiced the method. The results showed that the GASING method successfully changed the teacher's teaching paradigm to start learning from concrete to abstract stages. The approach using real objects proved to significantly increase students' interest, active participation, and quick calculation skills, including in students who previously had very low basic abilities. However, the teacher faced several challenges in its implementation, including the lack of comprehensive training time support from the school, passive student characteristics at home, and low student literacy levels that hindered the resolution of word problems. In conclusion, the GASING method was highly effective in creating deep and meaningful mathematics learning, but it required high commitment from teachers and systemic collaboration within the school environment.
