This article investigates the effect of kinesthetic educational game on students' mental computation speed. A Solomon four-group design was used to avoid the influence of pretest-posttest design. In order to determine which grade is appropriate for this game, a pilot study was conducted with 30 students. As for the main study, 123 students participated. First, the group was divided into two as control group and experimental group. The participants of the control group played a computer game while the members of experimental group played a kinesthetic educational game. According to Solomon, using a four-group model the study group was divided into 4 separate groups. The groups were randomly assigned and two of them were applied a pre-test. After the pre-test, in order to measure the attention level of students, a d2 test of attention was applied. The study lasted for 8 weeks in total. At the end of the study, a significant difference was found between the mental computation speeds of the experimental and the control groups. The second significant finding in this study was that there was a difference between the mental computation speeds of students depending on their cognitive characteristics. In other words, students with a low attention level finished the games in a longer period of time in comparison with students who have middle and high attention levels. It was concluded that students with a low attention level have lower mental computation speed. The results suggest that within primary school, Kinect-based exergames can be exploited as effective and motivational learning environments.