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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,*,2.4,米,0.8米,宣 传 栏,每平方米用0.9kg油漆,一共需要多少千克油漆?,小 数 乘 小 数,2.4,0.8= ?,1,.9,2,2,.,4,0 . 8,2,4,8,1,9,2,扩大到它的10倍,缩小到它的,100,1,扩大到它的10倍,看一看,因数与积的小数位数有什么关系?,1.92,0.,9,= ?,1. 7 2 8,1,.,9 2,0 .,9,192,9,1728,扩大到它的10,0,倍,缩小到它的,100,0,1,扩大到它的10倍,看一看,因数与积的小数位数有什么关系?,2,.,4,0.,8,=,1,.,9,2,2,.,4,0 .,8,2,4,8,1,9,2,先按整数乘法算出积。,一位小数,一位小数,二位小数,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。,1,.,92,0.560.04=,0,0.,5 6,0. 0,4,两位小数,两位小数,四位小数,乘得的积的小数位数不够,怎样点小数点?,0.0224,2 2 4,.,0,要在前面用0补足,再点小数点,计算小数乘法,先按照整数乘法的法则算出积,再看因数中一共有几位小数,就从积的右边数出几位,点上小数点。,不要计算,说出下表各栏的积是几位小数。,因,数,0.3,14.8,2.8,0.12,79,1.36,1.56,0.84,因,数,0.9,0.9,0.3,0.87,0.56,0.14,0.9,0.27,数学诊所,判断下面各个积的小数位数有没有错误。,56.7382154.6,0.370.943.478,41.29.23790.4,0.786.147.58,
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