教了几年二年级数学,始终为“认识角”的教学效果不佳而苦恼。如在教学“张口一样大,角就一样大,跟边的长短没有关系”这一内容时,我和许多教师一样,经常用课件图形重叠法或用三角尺重叠法比较两个角的大小,并说明“张口一样大,角就一样大,跟边的长短没有关系”。在多次的教学中,始终没有解决“角的大小与边的长短没有关系”的问题,在一次市名师送教下乡活动中,笔者用两块三个角分别相等的三角尺,选择相等的角,用不同颜色的粉笔重叠画出一个角,学生很快掌握了“角的大小与边的长短没有关系”的知识。所以笔者认为,用三角尺描线重叠法认识角与边的关系效果好。为了说明用三角尺描线重叠法认识角与边的关系时教学效果好,笔者举例用三角尺重叠法和三角尺 Teaching a few years of sophomore mathematics, has always been “cognitive angle ” poor teaching and distress. Such as teaching “open mouth as big, the same angle, with the length of the side does not matter ” This content, I, like many teachers, often with the courseware graphic overlay or triangle ruler overlap method to compare the two corners Size, and that “mouth open as big, the same angle, with the length of the side does not matter ”. In many teaching, has never been solved “corner of the size of the length of the side has nothing to do ” issue, in a municipal teacher sent to the countryside activities, the author with two three angles were equal to the triangular ruler, Select the same angle, with different colors of chalk overlap drawing a corner, the students quickly mastered “corner of the size of the length of the edge has nothing to do ” knowledge. Therefore, I believe that the use of trigonometric ruler line overlap method to recognize the relationship between the corner and the effect is good. In order to illustrate the triangle ruler line overlap method to recognize the relationship between the angle and the edge of the teaching effect is good, the author, for example, with triangular ruler overlap method and triangular ruler