This study aimed to determine the effectiveness of the NJJ (Negative Concepts, Join Forces, and Journey to Mastery) Triadic Approach in enhancing Grade 10 students’ skills in solving fraction problems involving the addition and subtraction of mixed and improper fractions. A quantitative research design was employed, specifically the one-group pretest-posttest method, a type of pre-experimental research. This design assessed the effects of the intervention by comparing student performance before (baseline) and after (end-line) its implementation. Additionally, the study sought to gather student insights regarding the use of the NJJ Triadic Approach in improving their ability to solve fraction problems. Thirty-nine Grade 10 students participated in the pre-test, underwent the NJJ Triadic Approach intervention, and completed the post-test. Ten participants were also selected for in-depth interviews. Results revealed that students initially demonstrated very low proficiency, with a mean pre-test score of 2.95% and a standard deviation of 1.17. Following the intervention, the mean post-test score increased to 22.18%, with a standard deviation of 3.38. While still within the very low range, this reflected a marked improvement. A paired samples t-test indicated a statistically significant difference between the pre-test and post-test scores, t(38) = 6.56, p < .001, with a large effect size (Cohen’s d = 1.05). These findings indicate that the NJJ Triadic Approach had a significant positive effect on students’ ability to solve fraction problems involving mixed and improper fractions. The results suggest that the NJJ Triadic Approach is an effective strategy for enhancing students’ skills in this area. Its implementation addressed common learning difficulties, making it a valuable tool for mathematics instruction. The researchers recommend the use of this approach to build foundational skills, improve student engagement, and boost learners’ confidence and motivation. Moreover, this student-centered model may be adapted for other mathematics topics that require strong conceptual understanding.