数学具有结构化的特点,一般来说每一个例题都是数学结构化知识网络的一个节点。由于教材篇幅及学生学习时间、空间的限制,在短短的一节课时间里,例题一般来说无法尽情表达其应有之意、无法穷尽其应有之变化,例题之后一般辅以若干变式练习以巩固所学知识,这些变式练习和例题相比呈现形式不同,难度深浅不同,但是知识基础相同,思维方法基本相同。如果说例题是某一类知识的根,那么练习题就是枝和叶,我们的教学应该是根深叶茂。但是,教材设计的例题和练习题虽然存在诸多联系,由于故事情 Mathematics has the characteristics of the structure, in general, every example is a node in the mathematical structured knowledge network. Due to the length of teaching materials and student learning time and space constraints, in a short period of class time, the examples in general can not express their due meaning, can not exhaust its due changes, after the example is generally supplemented by a number of changes Practice to consolidate the knowledge learned, these variant exercises and examples compared to different forms of presentation, different levels of difficulty, but the same knowledge base, the same way of thinking. If the example is the root of a certain kind of knowledge, then exercises are branches and leaves, our teaching should be deep-seated. However, there are many links between the examples and exercises in the textbook design due to the story