五年级5.8-积的小数位数不够的小数乘法市名师优质课比赛一等奖市公开课获奖课件.pptx

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,*,苏教版 数学 五年级 上册,积,小数位数不够小数乘法,情景,导,入,探究新知,课堂小结,课后作业,小数乘法和除法,课堂练习,5,第1页,情景,导,入,6.70.3=,6.7,0.3,1,先按整数乘法算出积,67,3,1,一位小数,一位小数,两位小数,.,再看因数中一共有几位小数就从积右边起数出几位，点上小数点。,2 0 1,.,0,2,0,2,第2页,九折,探究新知,例,1,小,明在阳台上摆放了一个花架，它底边是边长,0.28,米正方形。这个花架占地面积是多少平方米？,0.28,0.28,（,平方米,）,要从积右边起数出几位点上小数点？位数不够怎么办？,0.2 8,0.2,8,2 2 4,5 6,7 8 4,第3页,小明在阳台上摆放了一个花架，它底面是边长,0.28,米正方形。这个花架占地面积是多少平方米？,0.0784,答：花架占地面积是,平方米。,0.28,0.28,（,平方米,）,0.0784,在积里点小数点,时，位数不够，,在前面用,0,补足。,0.2 8,0.2,8,2 2 4,5 6,7 8 4,0,.,0,第4页,练一练,你能给下面各题积点上小数点吗？,0.7,0.9,6 3,1.0 5,0.0 6,6,3,0,0.1,8,0.3,5,4,.,.,.,0,0,0,0,0,第5页,课堂练习,0.430.15,(,),0.0645,4,添,0,第6页,填一填。,8.5,小数点先向右移动两位，再向左移动三位，结果是（）。,0.85,第7页,你,能给下面积点上小数点吗？,0,0,0,.,.,.,0,0,第8页,依据,1283,384,，直接写得数。,12.80.3,1.280.3,0.1280.3,0.1280.03,3.84,0.384,0.0384,0.00384,第9页,口算,。,2.50.4,0.10.3,0.1220,1.250.8,3.20.2,1.50.4,105.6,0.20.3,1,0.03,2.4,1,0.64,0.6,56,0.06,第10页,不,计算，说出下面各题,积,有几位小数。,2.35.4,0.250.37,8.10.04,0.092.004,2,位,4,位,3,位,5,位,第11页,计算下面各题，并用计算器验算。,0.270.15,0.0380.32,0.0491.42,0.140.32,0.183.2,0.030.84,0.0405,0.01216,0.06958,0.0448,0.576,0.0252,第12页,用竖式计算下面各题。,0.74,2.03 0.025,1.38,2,2.0,3,0.7 4,2,3,1.3 8,0.0 2 5,0,0,0,=1.5022,=0.0345,2,0,5,1,1,8,2,1,1,4,9,6,6,7,2,4,5,0,第13页,火眼金睛,辨对错。,更正：,0.018,第14页,更正：,633.6,第15页,更正：,0.042,第16页,一块长方形,铝板，长,0.84,米，宽,0.6,米；一块正方形铝板，边长,0.7,米。哪一块铝板面积大一些,?,大多少平方米,?,答：长方形铝板面积大,一些,大,0.014,平方米。,0.840.6,长方形铝板：,正方形铝板：,0.70.7,0.504,0.49=0.014,（平方米）,=0.504,（平方米）,=0.49,（平方米）,第17页,这节课你们都学会了哪些知识？,课堂小结,在积中点小数点，位数不够时，要在前面用,0,补位；积小数末尾有,0,，要先点上小数点，再依据小数性质进行化简。,第18页,1.,从教材课后习题中选取；,2.,从课时练中选取。,课后作业,第19页,