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1、第2课时 小数点的移动引起小数大小变化的规律（2）,R四年级下册,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,温故知新,说一说,我们已经学习了小数点的移动的有关知识，你知道小数点向左、向右
2、移动会引起小数怎样变化吗？,小数点向右移动一位，小数就扩大到原数的 10 倍；移动两位，小数就扩大到原数的()倍；移动三位，小数就扩大到原数的()倍；,100,1000,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路
3、,状元成才路,状元成才路,小数点向左移动一位，小数就缩小到原数的 倍；移动两位，小数就缩小到原数的()倍；移动三位，小数就缩小到原数的()倍；,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,
4、应用小数点移动引起小数大小变化的规律，可以把一个数扩大或缩小。,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,要解决这个问题，怎样列式呢？,（1）把0.07分别扩大到原来的10倍、100倍、
5、1000倍，各是多少？,0.0710 0.071000.071000,说一说你是怎么计算的。,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,0.07,扩大到原来的10倍,就是乘10,0.0710,就是把0.07的小
6、数点,向右移动一位,0.7,0.07,扩大到原来的100倍,就是乘100,0.07100,就是把0.07的小数点,向右移动两位,7,0.07,扩大到原来的1000倍,就是乘1000,0.071000,就是把0.07的小数点,向右移动三位,70,归纳小结,把 0.07 扩大到原来的 10 倍，就是10；把 0.07 扩大到原来的 100 倍，就是100；把 0.07 扩大到原来的 1000 倍，就是1000。,实际上就是把 0.07 的小数点分别向右移动一位、两位、三位。,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元
7、成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,（2）把3.2分别缩小到原来的，各是多少？,要解决这个问题，怎样列式呢？,3.210 3.21003.21000,说一说你是怎么计算的。,3.2,就是除以10,3.210,就是把3.2的小数点,向左移动一位,0.32,3.2,就是除以100,3.2100,就是把3.2
8、的小数点,向左移动两位,0.032,3.2,就是除以1000,3.21000,就是把3.2的小数点,向左移动三位,0.0032,缩小到原来的 倍,缩小到原来的 倍,缩小到原来的 倍,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路
9、,状元成才路,状元成才路,状元成才路,归纳小结,把 3.2 缩小到原来的 10 倍，就是10；把 3.2 缩小到原来的 100 倍，就是100；把 3.2 缩小到原来的 1000 倍，就是1000。,实际上就是把 3.2 的小数点分别向左移动一位、两位、三位。,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状
10、元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,1.把下面的数分别扩大到原来的10倍、100倍、1000倍。4.8 0.735 12.6,4.810484.81004804.810004800,0.735107.350.73510073.50.7351000735,12.61012612.6100126012.6100012600,说一说你是怎么想的。,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成
11、才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,2.把下面的数分别缩小到原来的。93.5 500 9999,93.5109.35 93.51000.93593.510000.0935,5001050 500100550010000.5,999910999.9 999910099.99999910009.999,四句歌,小数点移动要记牢；右移扩大、左移缩小；移动一（
12、二、三）位是10（100、1000）倍；位数不够“0”补位！,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,巩固练习,1.将 3.025 扩大 到原来的10 倍、100 倍、1000 倍分别
13、是多少？,3.0251030.253.025100302.53.02510003025,2.将 0.2 缩小到原来的10 倍、100 倍、1000 倍分别是多少？,0.2100.02 0.21000.0020.210000.0002,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成
14、才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,0,2 9 6,3.在括号里填上合适的数。,2.96,(),(),(),2 9 6,.,29.6,2 9 6,.,0,0.296,小数点向右移动位,小数点向左移动位,小数点向右移动位,一,两,三,.,296,4.我最棒，直接填得数。2.8710=3.91000=34.8110=21000=0.67100=12.5100=,0.002,3900,3.481,2.87,0.0067,1250,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路
15、,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,5.我会填.（1）把3.6的小数点向左移动一位是()。（2）把3.14的小数点向左移动两位是()。（3）把0.03扩大到它的()倍是30。,0.36,0.0314,1000,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元
16、成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,通过本节课的学习，你有哪些认识和收获？,课堂小结,课后作业,1.课本 P46，第 3 题、第 4 题；2.完成练习册本课时的习题。,声 明本文件仅用于个人学习、研究或欣赏，以及其他非商业性或非盈利性用途，但同时应遵守著作权法及其他相关法律的规定，不得侵犯本司及相关权利人的合法权利。除此以外，将本文件任何内容用于其他用途时，应获得授权，如发现未经授权用于商业或盈利用途将追加侵权者的法律责任。武汉天成贵龙文化传播有限公司湖北山河律师事务所,
