教学《三角形面积的计算》,在组织学生完成了教材内容的学习之后,我增加了一个课时的教学。我先说道:“同学们已经会用分、合两种思路,把两个完全一样的三角形转化成我们已经学过的平行四边形、长方形,然后推导出三角形的面积计算公式。如果只用一个三角形,你能想办法推导出三角形的面积计算公式吗?”学生有的独立思考,有的同桌讨论,有的小组研究。之后,学生汇报想法。谭月说:“我用的是一个等腰三角形。我发现,用剪拼的方法可以把一个等腰三角形剪拼成长方形 Teaching ”Calculation of the Area of ​​the Triangle“ After I completed the study of the contents of the teaching materials, I added a class time teaching. I first said: ”Students have already used the idea of ​​splitting and combining two identical triangles into the parallelogram and rectangle we have already learned, and then deduced the formula for calculating the area of ​​the triangle.If only one Triangle, can you think of ways to deduce the triangle area calculation formula? “Some students think independently, some of the same table discussion, and some group research. After that, students report their thoughts. Tan Yue said: ”I used an isosceles triangle .I found that the method of using shear splice can be an isosceles triangle cut into rectangular