The aim of the current research is to know the effect of teaching mathematics using the PDEODE teaching strategy supported by the e-learning environment in developing the conceptual understanding and problem-solving skills among the fourth grade of the primary stage. To achieve the research objectives, the experimental approach was in its quasi-experimental design. The research sample consisted of 76 students, divided into two groups; experimental, 38 students who studied using PDEODE supported by the e-learning environment, and control, 38 students who studied in the traditional method. The results showed firstly, there are statistically significant differences at the significance level 0.05 between the mean scores of the students in the two groups: experimental and control in the conceptual understanding test in favor of the experimental group students. Secondly, there are statistically significant differences at the significance level 0.05 between the mean scores of the students in the two groups: experimental and control in the test of problem-solving skills in favor of the experimental group students. Thirdly, there is a positive correlation between the scores of experimental group students in the conceptual understanding test, and their scores in the problem-solving skills test in mathematics.