“Effectiveness of Android-Based Learning Media “Teman Ritma” to Improve Problem-Solving Skills of SMP Negeri 5 Yogyakarta”. Jurnal Mercumatika : Jurnal Penelitian Matematika Dan Pendidikan Matematika, vol. 6, no. 2, Apr. 2022, https://doi.org/10.26486/jm.v6i2.2447.