【教学内容】浙教版四年级下册教材第18、19页改编。【教学过程】一、复习引入,直观认识出示:下面图形中,哪些是长方形?提问:我们已经认识了长方形。这些图形中哪些是长方形?哪些不是长方形?(2)、(3)、(5)这几个为什么不是长方形?预设:它们多了几个或者少了几个。过渡:像这样多摆了几个小正方形或者少摆了几个小正方形,它们肯定不是长方形。如果让你去摆一个长方形,你会吗? Teaching content】 【Zhejiang version of the fourth grade textbook page 18, 19 adaptation. [Teaching process] First, review the introduction, intuitive understanding Show: The following graphics, which are rectangular? Question: We have met the rectangle. Which of these graphics are rectangular and which are not rectangular? (2), (3), (5) why these are not rectangular? Default: a few more or a few of them. Transition: Like this put a few small square or less placed a few small square, they are certainly not rectangular. If you let go for a rectangle, will you?