Problem-solving skills, specifically in solving routine and non-routine problems involving areas of squares and rectangles, are foundational to various mathematical concepts; however, learners consistently find these concepts challenging to master. This study at San Rafael Integrated School (2023-2024) investigated the impact of using Lego kits to teach Grade 3 students how to solve routine and non-routine problems involving the areas of squares and rectangles. Using a quasi-experimental methodology, two groups of 30 students each were compared: a control group taught with traditional methods and an experimental group taught using Legos. Pre-test results indicated that neither the control nor the experimental group met the expectations set by the K to 12 grading system, with 7.41 and 9.12 scores. Although both groups exhibited similar initial proficiency levels, the notable difference in pre-test scores can be attributed to various factors (including the students' value for mathematics). However, despite their appreciation for the subject, many still struggle with fundamental skills and concepts; this may have influenced their performance in the pre-test. Post-test results (however) revealed a significant improvement in the experimental group's performance, with a mean score of 25.28 compared to the control group's 16.07. The findings demonstrate the superior efficacy of the Legos as a manipulative kit over traditional methods in solving routine and non-routine problems involving areas of squares and rectangles. Thus, teachers may incorporate Legos as manipulative kits early in the school year to provide a visual and tactile learning experience that helps students build a concrete understanding of mathematical operations.