数学学习活动的建构需要建立在教材与学生的基础之上,教材不能信手拈来,拿来就用,还要结合实际情况,对教材和学生进行解构。这就好比,建造楼房前,要对实地进行考察,进而画出合适的设计图,再施工。这个考察就是解构,这个设计就是建构,唯有此,万丈高楼才能平地起。因此,只有完全地、深入地解构,建构才能扎实、有效地构造、建立。下面,笔者就苏教版数学四年级(下册)《三角形的认识》一课的教学实例谈一谈在解构与 The construction of mathematics learning activities needs to be based on teaching materials and students, teaching materials can not come in handy, brought to use, but also with the actual situation, the deconstruction of textbooks and students. This is like, before building a building, we should inspect the field, and then draw the appropriate design drawings, and then construction. This study is deconstruction, this design is to construct, only this, towering high buildings in order to play. Therefore, only by completely and in-depth deconstruction can the construction be established and established in a solid and effective manner. Next, the author on the Sujiao version of mathematics fourth grade (second volume) “Triangle Recognition” a teaching example to talk about the deconstruction and