【教材分析】:本课教学内容是国标本六年级(下)的“图形的放大和缩小”。教材在这部分的编写,出于两点考虑:一是根据放大(或缩小)前后两个图形中相对应的数据,能够写出许多相等的比,这是教学比例知识的极好素材,有益于学生数形结合,感悟比例的意义。二是借助比例能清晰地表达图形放大与缩小的规律,从而加深对图形放大与缩小的理解。【学生情况】 【Textbook Analysis】: The teaching content is the sixth grade of the national standard (below) “zoom and zoom graphics.” Textbook in this part of the preparation, for two considerations: First, according to the enlarged (or reduced) before and after the two graphics corresponding to the data, you can write many equal ratio, which is an excellent material for the proportion of teaching, useful The number of students in the combination of perception of the significance of the ratio. The second is by means of the ratio can be clearly expressed graphics zoom in and out of the law, so as to deepen the understanding of graphics zoom in and out. 【Students】