苏教版五年级数学上册第九册小数乘小数2ppt课件

单击此处编辑母版标题样式,qing zhen shi wang zhuang xiao xue guo kai xin,苏教版小学数学五年级上册,复习稳固,3,5,.,2,1,.,5,3,0,7,5,3,7,.,1,.,6,2,.,2,5,0,1,8,4,2,3,0,5,0,4,.,复习稳固,不要计算，说出下表各栏的积是几位小数。,乘数,0.3,14.8,2.8,0.12,79,1.36,1.56,0.84,乘数,0.9,0.9,0.3,0.87,0.56,0.14,0.9,0.27,新知讲解,8,小明在阳台上摆放了一个花架，它的底面是边长,0.28,米的正方形。,房,间,阳,台,门,0.28,米,新知讲解,8,这个花架的占地面积是多少平方米？,0.280.28 ,0,.,2,8,0,.,2,8,4,2,2,6,5,4,8,7,一共四位小数,位数不够，怎么办？,在前面补,0,四位小数,0.28,米,0,新知讲解,8,这个花架的占地面积是多少平方米？,0.280.28 ,0.28,米,0,.,2,8,0,.,2,8,4,2,2,6,5,4,8,7,在前面补,0,0,.,0.0784,平方米,答：这个花架的占地面积是,0.0784,平方米。,归纳总结,小数乘小数的计算方法：,先按照,整数乘法,的计算方法算出积，再看,乘数中一共有几位小数,，就在积的,右边数出几位，点上小数点,。,如果积的位数不够，在前面用,0,补足,。,练一练,你能给下面各题的积点上小数点吗？,0,.,0,.,0,0,.,练一练,乘,数,45,45,0.45,0.45,45,0.045,乘 数,16,1.6,1.6,16,0.16,1.6,积,720,根据第一栏的积，写出各栏的积。,7.2,0.72,7.2,7.2,0.72,