[文1]中指出:新课程背景下的数学课堂教学,要注意处理好六种关系,其中之一就提到了要处理好“进”与“退”的关系·笔者读后深受启发·古语云:“治国之道,有所为,有所不为”·数学教学也是如此·“有所为”的地方就是该“进”的地方,“有所不为”的地方就是该“退”的地方·课? [1] pointed out that: In mathematics classroom teaching under the background of the new curriculum, we must pay attention to dealing with six kinds of relationships. One of them mentions the need to handle the relationship between “advancement” and “retreat”. As the old saying goes, “The way to govern the country is something to do and something to be done.” • Mathematics teaching is also the case. “Things that do something” are the places where the “jinjin” comes from. The place that “does nothing” is the “retreat”. “Places and classes?”