Abstract
Language mismatch poses challenges for students, particularly those from public schools, as they struggle to comprehend and solve math problems presented in a language different from their primary medium of instruction. Thus, this study investigated the perceptions of Mathematics teachers in Grades 1–3 regarding Mother Tongue-Based (MTB) instruction and its impact on students' performance in the Metrobank-MTAP-DepEd Math Challenge (MMC) in the Tubigon East and West Districts. Using a descriptive correlational design, data were collected from 107 public school teachers via a validated questionnaire and analyzed using weighted means and chi-square tests. Teachers rated their strategies highest (M = 4.26, SD = 0.51), followed by language competence (M = 4.05), sufficiency of teaching materials (M = 3.77), and learners' learning level (M = 3.69), with an overall perception mean of 3.94 (Agree). However, perceptions of MTB's effect on MMC performance were low (M = 2.07, Disagree). Significant relationships were found between perceptions of MTB instruction and years of teaching (p = 0.002) and MMC participation (p = 0.000), but none with perceptions of its effect on MMC performance. While MTB is viewed as effective for classroom teaching, its benefits do not extend to MMC outcomes due to language mismatch. Recommendations include bilingual review materials and targeted training.