Abstract

This article clarifies the theoretical foundations for developing students’ mathematical thinking and reasoning competence and proposes a set of pedagogical measures to enhance the effectiveness of competency- based mathematics instruction. Each measure is illustrated with specific examples from the topic of trigonometric relations in triangles, thereby demonstrating how learning activities can be organized and highlighting the teacher’s role in guiding the cognitive development of students at Van Xuan High School. The proposed measures adopt an open and flexible approach, allowing them to be adapted to the characteristics of different student groups and the practical conditions of individual educational institutions.

Keywords: High school students, mathematical reasoning competence, mathematical thinking competence, mathematics teaching and learning, trigonometric relations in triangles.