This study investigated the effect of PowerPoint (PPT) instruction on achievement in two categories of SHSs in Ghana; less endowed and endowed schools, using a pre-test post-test quasi-experimental design. The sample consisted of 80 randomly selected students from two purposively selected government-assisted SHSs. The instruments used for data collection were two similar adopted Pre- and Post-Geometry Achievement Tests (GAT). During treatment, PPT presentations were used to teach both groups, some selected topics in geometry. Analysis of pre-GAT scores of both groups revealed that the participants in the endowed group significantly outperformed their counterparts in the less endowed group by a mean difference of 9.20. The results from the independent samples t-test conducted also showed that the endowed group significantly outperformed the less endowed group in the post-GAT. However, the results showed that the mean difference recorded between the two groups in the pre-GAT was significantly reduced to 6.58 in the post-GAT. Finally, the findings revealed no influence of gender in the achievement of both groups when PPT presentation was used in the instructional delivery. In conclusion, the use of PPT presentations in mathematics was found to increase SHS students’ achievement in mathematics and also found to be a good instructional approach that can be employed to narrow the gap in achievement levels between endowed and less endowed SHSs. The implications for practice and research are discussed.

Keywords: PPT Presentation, Endowed, Less endowed, Mathematics, Achievement, Gender