Strengthening Logical Thinking in Children Aged 5-6 Years Through BUMIKA Geometry: A Classroom Action Research Study

Abstract

Logical thinking in early childhood underpins children’s ability to compare quantities, organize sequences, classify objects, and reason about number. This study examined the development of logical-thinking skills in children aged 5–6 years through BUMIKA Geometry, a manipulative learning medium that integrates counting, sequencing, comparing, and classifying activities using geometric pieces, a sorting box, and a stacking tower. The study used participatory classroom action research in one Group B classroom at TK Tunas Harapan 1 Ciputat, Indonesia. Twelve children participated in two iterative cycles consisting of planning, action, observation, and reflection. Cycle I comprised six meetings and Cycle II four meetings. Data were collected through structured observation, classroom interviews, field documentation, and learning records, then analyzed descriptively using quantitative percentages and qualitative reduction, display, and interpretation. The mean logical-thinking score increased from 40.28% at pre-action to 51.37% in Cycle I and 76.91% in Cycle II, an overall gain of 36.63 percentage points. Cycle II averages were 78.40% for comparing, 78.65% for sequencing, 74.91% for classifying, and 76.82% for counting. Qualitative evidence indicated greater independence, participation, and sustained attention after the Cycle II classroom-management revision. The findings suggest that an integrated, concrete, play-oriented medium can support logical-thinking practice in authentic early-childhood classrooms. Because the study involved a single class without a comparison group, the results should be interpreted as within-class improvement rather than causal evidence.