Effects of Polya’s Problem-Solving Approach Combined with the Bar Model Technique on Grade 4 Students’ Problem-Solving Ability in Addition and Subtraction of Whole Numbers Greater than 100,000 at Piboonsawasdee Municipal School, Phuket Province

Abstract

This research aims to 1) develop Grade 4 students’ problem-solving ability, with a success criterion of at least 60% of the total score, and 2) compare students’ learning achievement before and after the intervention. The target group comprised 34 Grade 4/2 students at Piboonsawasdee Municipal School in the first semester of the 2025 academic year (B.E. 2568), selected through purposive sampling. Research instruments included 10 lesson plans (10 hours), a five-item constructed-response problem-solving test, and a 20-item four-option multiple-choice achievement test. Data were analyzed using percentages, means, standard deviations, a one-sample t-test to compare the mean score with the criterion, and a paired-samples t-test to compare pretest and posttest achievement.

          The results showed that 1) the students’ mean score for problem-solving ability was 43.71 out of 50 points (87.41%), which was significantly higher than the 60% criterion at the .05 level of significance. In terms of Polya’s problem-solving steps, the students were able to carry out each step correctly. 2) The students’ post-intervention learning achievement was significantly higher than their pre-intervention achievement at the .05 level of significance, with the mean score increasing from 11.85 to 16.85 out of 20 points.