الملخص الإنجليزي
The study aimed to investigate the effectiveness of using the GeoGebra software in teaching functions on the achievement of grade eleven ( male students ) in the sultanate of Oman and equip them transformations geometry skills. The study used quasi- experimental design with two groups; an experimental group consisted of (30) students and control group consisted of (27) students who were randomly selected from Saif bin Sultan (11-12) school. The experimental group studied functions using the GeoGebra software, while the control group studied the same unit by the traditional method. The study made sure that there were equivalence between the two groups concerning the previous achievement and transformations geometry skills. The material of the study consisted of a teacher's guide to teach functions using GeoGebra software. It was examined and checked by a group of specialists for validity. In order to find the effectiveness, the researcher constructed three tools, a pretest in transformations geometry skills, a post-test in transformations geometry skills and a test of achievement. They were reviewed by a group of specialists for validity. The reliability of the first test was (0.8), the second test was (0.83) and the third one was (0.82) according to the Coronbach-Alpha measuring method. After finishing the experiment, post-tests were given. To analyze data, the study used the means, standard deviation, and T-test, this study reached the following findings: - There was a statistically significant difference at level (as ,xo) between the students' scores means in the experiment and the control groups in the achievement test, in favour of the students taught using GeoGebra - There was a statistically significant difference at level (as...) between the students' scores means in the experiment and the control groups in the transformations geometry skills test, in favour of the students taught using GeoGebra. In light of these results, the researcher recommends introducing GeoGebra software in teaching mathematics
