在三年级的“面积”练习课上,我出示了一道练习册上有关组合图形的面积计算的题目:把两张边长分别为6cm和3cm的正方形纸片拼成图1所示的图形,求所拼成图形的面积和周长。这道题虽说是在《面积》单元学完之后出现的,但对于小学三年级的学生来说是第一次接触,有一定的难度。为此,备课时我把问题分两课时教学——“求所拼成图形的面积”放第一课时,“求所拼成图形的周长”放第二课时。对于求 In the third grade “area ” practice class, I presented an exercise book on the area of ​​combo graphics calculation of the title: the two sides of the 6cm and 3cm square pieces of paper respectively, as shown in Figure 1 Graphics, seek the area and circumference of the graphics. Although this question arose after the completion of the “area” unit, it was a certain difficulty for the third-grader of primary school to contact for the first time. For this reason, when preparing lessons, I divided the problem into two classes, teaching - “seeking the area of ​​the figure to be put together,” and putting the first lesson. For seeking