Scienceline Publications Journal of Educational and Management Studies 2322-4770 8 3 2018 September Cooperative learning instructional approach for students’ mathematics achievement and attitude towards mathematics: a case study on probability and statistics lesson at a governmental secondary school in Ethiopia 56 63 jems.science-line.com/attachments/article/44/J.%20Educ.%20Manage.%20Stud.,%208(3)%2056-63,%202018.pdf EN Dejene Girma Denbel Assistant Professor, Dilla University, College of Natural and Computational Science, Department of Mathematics, Dilla, Ethiopia Introduction: The purpose of this study was to see the impact of cooperative learning on mathematics achievement and attitude towards mathematics at secondary school mathematics. The study significantly reflected the case study of grade eleven students in a secondary school, Ethiopia. Approach: quasi-experimental study done on two selected teams. Random assignment was done, one category (n = 51) was allotted to associate experimental group and therefore the other (n = 51) was allotted as a control group. The two teams were pre-tested previous the implementation of the intervention. Post-test given at the end of intervention; whereas daily quiz used as a tool for formative testing. Teaching and learning method administered for 2 weeks. Data were analysed using the paired t-test to determine performance by comparing the mean of the post-test for treatment and control groups at the significant level of p / 0.05. Results: The result has shown by strong evidence (t = 2.285, p = 0.027) that the teaching of mathematics through cooperative learning approach improves their achievement score. Moreover, it had been evidence (t = 4.45, p = 0.0001) that the teaching of mathematics through cooperative learning approach higher attitude towards mathematics. Conclusion: From the result, a cooperative learning approach facilitated the instruction for this explicit topic. Therefore, those mathematics teachers have to be required to incorporate in their teaching of mathematics at secondary school. In fact, it is needed further study to generalize this result to a bigger domain. Cooperative learning approach Mathematics Achievement Attitude