数学教学是要引导学生自己寻求知识产生的起因,探索数学知识与其他事物的联系,在探索的过程中形成概念、寻求规律、获得结论.现以“相交线中的角”的教学为例,谈谈通过设置有效问题,让学生经历概念的形成过程的具体做法.一、以旧引新创设问题情境由于三线八角是在两条相交直线的基础上再增加一条直线所形成的图形,所以三线八角可以看成是两条相交直线的进一步拓展.为此,笔者从学生原有的认知——相交的两直线出发,通过动手操作,引入了相交的三直线的位置情况,为学生了解三线八角中 Mathematics teaching is to guide students to seek the cause of knowledge production, to explore the connection between mathematical knowledge and other things, to form concepts, to seek the law and to get the conclusion in the process of exploration. For example, to talk about through the set of effective questions, so that students experience the concept of the formation of the specific approach.One, the old problem with the creation of new problems As the three-line angle is based on the two intersecting lines to add a line formed by the graphics, Therefore, the three lines and eight angles can be seen as two intersecting lines to further expand.Therefore, the author from the original cognition of students - the two lines of intersection, through hands-on operation, the introduction of the intersection of three straight line position for students Understand the three lines