AU - الأحمدي، سعاد مساعد سليمان AB - This study aims to examine the effect of using Mathletics website on the development of academic achievement in mathematics of intermediate school female students in the city of Riyadh. The researcher uses quasi-experimental methodology for independent groups to examine the effect of the independent variable, which is the use of Mathletics website on the dependent variable, which is mathematical achievement. The study sample consists of (283) second year intermediate female students from three intermediate schools. They are selected by purposive sample method (two classes per each school). Then, they are divided into two groups: The first group consists of (88) female students representing the experimental group who activate Mathletics website during their study of the linear functions unit in algebra. The second group consists of (195) female students representing the control group who do not activate Mathletics website during their study of the linear functions unit in algebra. The achievement test is administered before and after the end of the study unit. The statistical software package SPSS was then used to analyze the data. The results show that there is a statistically significant difference at the level of (0.01) between the mean scores of the experimental and control groups in the post-test in the total score of the achievement test in mathematics in favor of the mean scores of the experimental group. Also, the eta squared value, which is equal to (0.1565), indicates that 15.65% of the variation in the total scores of the achievement test in mathematics can be explained. It means that there is a significant impact of using Mathletics website on the development of the total score of academic achievement in mathematics of second year intermediate female students in the experimental group compared to the control group. In addition, the researcher has found that there is a statistically significant difference at the level of (0.01) between the mean scores of the experimental group in the pre- and post-test in the total score of achievement test in mathematics in favor of the mean scores of the post-test. The eta squared value, which is equal to (0.6910), indicates that 69.10% of the variation in the total scores of the achievement test in mathematic scan be explained. This means that there is a significant impact of using Mathletics website in the development of the total score of academic achievement in mathematics in the post-test compared to that in the pre-test among second year intermediate school female students in the experimental group. In light of the above findings, the researcher concludes that female students in the experimental group who activate the website during the study of the unit perform better than female students who do not activate the website. Emphasizing its importance, the researcher recommends using Mathletics website for female students for studying the mathematics course. (Published abstract) http://search.shamaa.org/abstract_en.gif OP - ص ص. 243-290 T1 - أثر استخدام موقع ماثلتيكس (Mathletics) في تنمية التحصيل الرياضي لدى طالبات المرحلة المتوسطة بمدينة الرياض [مقال] UL - 2 https://units.imamu.edu.sa/deanships/SR/Units/Vice/Magazines/Documents/%d9%85%d8%ac%d9%84%d8%a9%20%d8%a7%d9%84%d8%b9%d9%84%d9%88%d9%85%20%d8%a7%d9%84%d8%aa%d8%b1%d8%a8%d9%88%d9%8a%d8%a9/%d8%aa%d8%b1%d8%a8%d9%88%d9%8a%d8%a9%20%d8%b9%d8%af%d8%af%209.pdf محتوى العدد