Abstract. Mastery of basic arithmetic in grade one is a crucial stage in developing complex mathematical operations. During this stage, learners begin to acquire concepts that are necessary for the foundation of numeracy. Hence, the learners’ difficulty in attaining the basic skills of addition and subtraction must be improved; thus, this action research was conducted to minimize learning gaps. This study utilized a one-shot pretest-post-test quasi-experimental quantitative design to examine the effectiveness of interleaved practice as a remedial intervention strategy for enhancing proficiency in addition and subtraction operations among grade one pupils. Specifically, this determined 1) the level of performance of grade one learners in the basic operations of addition and subtraction using: a. traditional blocked practice and b. interleaved practice, 2) a significant difference in the mean scores between the learners under traditional blocked practice and those under interleaved practice, and 3) a significant mean gain between the pretest and posttest scores of learners between traditional blocked practice and interleaved practice. The grade one low-performing learners were selected through their second-trimester grade in Mathematics and the keen observations and feedback of Mathematics teachers during their class activities with the limited sample sizes of 15 for interleaved practice and 15 for traditional blocked practice. The researcher utilized Wilcoxon’s Signed Rank Test and Mann-Whitney U-test. Results have shown a significant improvement in the performance of the grade one pupil using both interleaved and traditional blocked strategies. Moreover, both interleaved and traditional blocked practices show an approximate equivalency of performance in terms of improving the skills of the learners. Thus, interleaved practice is an effective strategy to substitute the traditional blocked practice in remediating arithmetic skills in grade school. Still, further studies are recommended to test the long-term effect of the interleaved practice in remediating basic arithmetic operations.

Keywords: Interleaved practice; Traditional blocked practice; Arithmetic proficiency; Remediation