John Alexis O. De Vera, Ranao Elementary School, Department of Education, Bani District, Division of Pangasinan I, Philippines.

This action research examined the association between flash card interventions and improvements in mathematical performance among Grade 4 learners, specifically targeting multiplication skills development. Employing a quasi-experimental one-group pretest-posttest design, the study involved thirty-six Grade 4 learners enrolled at Ranao Elementary School during the 2022-2023 academic year. Data were collected through validated twenty-five-item pretest and posttest assessments focusing on two-digit multiplication problems. Statistical analysis using mean scores, mean percentage scores, and paired samples t-test revealed significant improvements in mathematical performance following the eight-week flash card intervention. Pretest results showed a mean score of 10.47 (41.9%) which increased to 12.92 (51.7%) in the posttest, representing a statistically significant difference [t(35) = -8.82, p < 0.001]. Effect size analysis revealed a large practical significance (Cohen's d = 0.98). The findings suggest that systematic flash card implementation is associated with enhanced multiplication computational fluency and accuracy among Grade 4 learners. This research contributes to evidence-based pedagogical practices in elementary mathematics education, particularly in addressing multiplication learning difficulties in the Filipino context. The study provides practical implications for teachers seeking effective, low-cost instructional strategies to improve basic mathematical skills.