<![CDATA[Despite the growing integration of technology in mathematics education, research on mobile learning platforms embedding local cultural contexts—particularly ethnomathematics—remains limited at the junior secondary level in Indonesia. Mathematical problem-solving ability remains a persistent challenge among students, necessitating Android-based learning media as a more engaging instructional solution. This investigation examined the extent to which an Android-based interactive mobile learning (m-learning) platform, integrated with ethnomathematics derived from Pontianak's local culture. A quasi-experimental posttest-only control-group design was adopted for this purpose. From nine classes at SMP Negeri 2 Pontianak, 60 participants were selected via cluster random sampling—30 in the experimental group receiving m-learning instruction and 30 in the comparison group receiving instruction without m-learning. Assessment of mathematical problem-solving capacity was conducted through a descriptive test comprising three items structured around Polya's four-stage indicators, with empirically established validity coefficients ranging from 0.94 to 0.96 and a reliability coefficient of 0.78. Statistical examination involved a one-tailed independent samples t-test for group comparison, supplemented by Cohen's d for effect size quantification. Findings revealed that learners exposed to m-learning instruction demonstrated substantially superior mathematical problem-solving performance compared to their counterparts in the conventional group (mean = 84.67 vs 72.63; p < 0.05), with a large effect magnitude (Cohen's d = 1.3). These outcomes affirm that the ethnomathematics-embedded Android-based m-learning platform constitutes an efficacious and educationally meaningful intervention for cultivating students' mathematical problem-solving proficiency. Nevertheless, further research on a broader scale is warranted to enhance the generalizability of these findings, along with the incorporation of a pretest to more rigorously assess gains and establish stronger causal evidence of the intervention's effectiveness.]]>
