Mathematics plays an important role in the school curriculum. Students face a number of challenging situations while solving problems in mathematics. They feel happy when they arrive at the correct solution but at the same time if they are unable to solve problems they find it difficult since mathematics has different language where symbols occupy an important role, so some students find it difficult to comprehend the subject.The present study has two major aspects, one was the development of PLM and another was to study the effectiveness of the developed PLM.Fourteen control group students and fourteen experimental group students were selected for the study. Collected data were analyzed through appropriate statistical techniques. To study the effectiveness of the developed PLM Mean, Standard deviation and Correlated t-test (small group) were computed.The prepared PLM in PROBABILITY was found effective in teaching PROBABILITY to XI standard science stream of GSHSEB students as the unit test score of experimental group students was found significantly higher than the unit test score of control group students.Thus PLM can be used along with the usual conventional classroom teaching