The Impact of instructional multimedia on learning and retention of mathematics of fourth grade educable Mentally Retarded girl Students of elementary schools in Arak City

The aim of this research was to examine the impact of instructional multimedia on learning and retention of mathematics of fourth grade educable mentally retarded girl students of elementary schools in the Arak city.The quasi-experimental research method has been used. The statistical population include all fourth grade educable mentally retarded students of elementary schools in the Arak city and the sample included all the statistical population, that were randomly assigned into an experimental and a control group. While the experimental group received three training sessions with a researcher made instructional multimedia software, the control group was trained with the conventional method without using the multimedia. In order to study the probable resulting changes, first, a pre-test was applied on both groups. After running the test, the experimental group was exposed to the independent variable. Both groups underwent the post test, and a second post test was performed to measure the retention after a two weeks time. The statistical analysis was descriptive and inferential statistics. Findings showed that learning and retention rates of students in the experimental group as compared with the control group were significantly increased. Overall, the results of the research show the excellence of learning and retention rates of students who had received training through multimedia software. Based on the results, it can be recommended that instructional multimedia can be useful in teaching and learning of mathematics for this group of students.