中学数学教材中有許多地方学生学习起来往往感到困难。一般的說,这些困难是由于在学生的认識基础与知識的要求之間存在着某些差距而引起的,解决难点的过程就是縮短和消灭差距的过程。因之解决难点的方法就要依据縮短和消灭差距的需要而定,而且也只有依据这种需要定出的方法才能有效的解决难点。 Many middle school students find it difficult to learn in many mathematics textbooks. In general, these difficulties are caused by certain gaps between the students’ understanding of knowledge and the requirements of knowledge. The process of solving difficulties is the process of shortening and eliminating gaps. The solution to this difficulty is based on the need to shorten and eliminate the gap, and it is only in accordance with the method set out in this need that the difficulty can be effectively solved.