Haimbodi, Frans NdemupondakaShilamba, Klaudia N.2026-06-232026-06-232025http://hdl.handle.net/11070/4259A thesis submitted in partial fulfilment of the requirements for the Degree of Master of EducationIn Namibia, Mathematics education faces persistent challenges, particularly in learners' grasp of Algebraic Expressions, as evidenced by consistent underperformance in national examinations. This study investigated the potential of Activity-Based Instruction (ABI) to enhance Grade 11 learners' proficiency in Algebraic Expressions, aiming to address these mathematical deficits. This research employed a mixed-methods approach to examine the impact of ABI. Qualitative insights were gathered from Mathematics teachers in the Onankali Circuit regarding their perceptions and experiences with ABI in teaching Mathematics. Concurrently, a quasi-experimental design with non-equivalent pretest posttest was utilised. Two Grade 11 classes, one from each of the two selected schools, in the Onankali Circuit, totalling 80 learners, participated in the study. The experimental group underwent ABI sessions, focusing on hands-on activities and interactive learning approaches, while traditional methods of instruction were utilised to teach the control group. The two groups were assessed via pre-tests and post-tests on Algebraic Expressions to gauge their performance improvements following the interventions. Statistical analysis revealed a substantial increase in the mean post-test score for the experimental group (31.55) in comparison to the mean post-test score for the control group (19.05). The results indicated that a statistically significant difference exists in the mean post-test score for the experimental group and the mean post-test score for the control group, at the significant level of 𝛼 = 0.05. This disparity highlights the effectiveness of ABI in enhancing learners' understanding and application of algebraic concepts. Mathematics teachers reported positive perceptions of ABI, noting increased student engagement and improved learning outcomes. However, challenges such as time constraints, limited resources, and technical difficulties were identified as barriers to optimal ABI implementation. These results could inform Ministry of Education to emphasise alternative teaching approaches in Mathematics education. The study recommends that mathematics teachers should be encouraged to employ ABI when teaching Algebraic Expressions, which can be facilitated by providing comprehensive training for Mathematics teachers on designing hands-on activities and implementing ABI in teaching Algebraic Expressions; and that the Ministry of Education, Arts and Culture should design a Continuous Assessment form for Mathematics Grades 10 -11, so that learners are assessed in every topicenActivity-Based Instruction (ABI)Algebraic expressionsGrade 11 LearnersLearners’ performanceLearners’ engagementNamibiaUniversity of NamibiaThesis