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单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,*,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,*,小 数 乘 小 数,第二课时,回顾反思,自主练习,合作探索,情境导入,一、情境导入,你会计算这三道题吗？,0.150.09=,0.480.06=,1.41.25=,0.2 8 8,0.4 8, 0.0 6,0.0 2 8 8,0.4 8, 0.0 6,0.480.06=,？,0.288,你会计算,0.480.06,吗？,二、合作探索,积是,0.288,还是,0.0288,？为什么？,0.0288,？,继续,0,0,.,.,.,.,0.4 8, 0.0 6,2 8 8,添,0,补位,0.0288,0.480.06=,？,积的小数位数不够怎么办？,二、合作探索,两位小数,两位小数,四位小数,你会计算,0.480.06,吗？,0.150.09,0. 0,1 3 5,0. 1 5,0. 0 9,0.0135,1.,你会计算,0.150.09,和,1.41.25,吗？,1.41.25,5 0 0,1. 2 5 1. 4,1.75,1 2 5,1,.,7 5,0,试一试,0.0 2 3, 0.4,0.0 0 9 2,1.0 5, 0.0 2,0.0 2 1 0,试一试,2.,用竖式计算。,计算小数乘法时，先按整数乘法的计算法那么来计算，再看因数中一共有几位小数，就从积的右边起数出几位，点上小数点。小数末尾有0要去掉，小数前面位数不够用0补上。,想一想，怎样计算小数乘法？,1.,计算小高手。,0.0 9, 0.8,0.0 7 2,0.4 7, 0.2,0. 0 9 4,0.4 3, 0.1 6,0.0 6 8 8,三、自主练习,2.,先判断积的小数位数，再计算。,0.1 2 4, 0.9,0.1 1 1 6,0.0 5 7, 0.0 6,0.0 0 3 4 2,0.4 6, 0.0 3,0.0 1 3 8,三、自主练习,3.,0.6,米,0.85,米,0.72,米,0.850.6=0.51平方米,三、自主练习,0.720.72=0.5184平方米,0.51,平方米,0.5184,平方米,0.5184-0.51=0.0084平方米,答：,正方形,的面积大，大,0.0084,平方米。,哪个图形的面积大？大多少平方米？,4.,在 里填上,“,”,、,“,三、自主练习,5.妈妈为喜欢读书的莉莉办了一张借书证如右图，这张借书证的面积是多少平方分米？,1.2,分米,0.8,分米,= 0.96平方分米,答：借书证的面积约是,0.96,平方分米。,三、自主练习,1.20.8,4,402,0.402,6.,连一连。,三、自主练习,40.2,4.02,0.0402,1343,13.43,1.340.3,1.343,1.340.03,
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