Habibie, A. F.; Handoyo, R. R. Concrete Representational Abstract Number Boards Optimize Slow Learner Statistical Data Mastery: Papan Bilangan Konkret Representasional Abstrak Mengoptimalkan Penguasaan Data Statistik Siswa Lamban. acopen 2026, 11, 10.21070/acopen.11.2026.15161.