Effectiveness of A strategy based onSelf-Regulated Learning in developingthe level ofMathematical Reasoning for 3th preparatory students

The objective of the research is to investigate the effectiveness of a strategy based on Self-Regulated Learning in developing Mathematical Reasoning for third grade preparatory students. was selected and its strength was (61) was selected from the third preparatory grade students from khatam Al-Morsalin Preparatory Model Secondary Institute of the Al-Siddiq Educational Administration, in Al-Giza Al-Azhar where random division into two groups: an experimental (30) students, and a control group (31) students, and the researcher distributed the experimental materials (teaching manual, science guide, student guide), building the research tool as a tool and setting it in a test: Mathematical Reasoning,and after applying the tools beforehand and making sure that the two research groups were equal in the test Mathematical Reasoning, The Research experiment was carried out where the experimental group studied, according to the strategy based on Self- Regulated learning, and the control group studied in the usual way. And after applying the research tools dimensionally to the two groups of research, the data, its statistics using the (SPSS v.24) program, The results of the research revealed the effectiveness of the strategy based on self- Regulated learning in the development of mathematicalReasoning for the third preparatory students, and the size of the calculated effect was large. In light of the results of the research, Researcher recommends employing a strategy based on self- Regulated learning when learning mathematics in the different educational stages to develop mathematicalReasoning.