根据我给准备任高中数学教师的大学生们讲课的经验,关于绝对值这一单元,宜采用下面的方法进行教学。我使用实数绝对值的五个定义。学生们可依据这五个定义,采用五种不同的方法解同一个习题。当他们发现定义的选择是如何影响到他们的思维过程时,就会受到极大的启发,从而更加深入地了解定义的作用。 According to my experience of giving lectures to undergraduates preparing to serve as high school mathematics teachers, the unit of absolute value should adopt the following method for teaching. I use the five definitions of the absolute value of real numbers. Students can use the five definitions to solve the same problem in five different ways. When they find out how the choice of definitions affects their thinking process, they are greatly inspired to learn more about the role of definitions.