小数乘以整数2

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,*,小数乘以整数,复习,说说下面每组数由第一个数到第二个数，小数点是怎样移动的？小数的大小发生了什么变化？,65,6.5,0.37,37,5,0.005,2.4,0.024,15,15,15,15,X,5,=,75,75,75,75,0,00,000,0,00,000,一个因数不变，另一个因数扩大,10,倍、,100,倍、,1000,倍,积也扩大,10,倍、,100,倍、,1000,倍,4,4,4,4,3,X,12,12,12,12,000,00,0,000,00,0,一个因数不变，另一个因数缩小,10,倍、,100,倍、,1000,倍,积也缩小,10,倍、,100,倍、,1000,倍,=,一个因数不变，另一个因数扩大（或缩小）,10,倍、,100,倍、,1000,倍,积也扩大（或缩小）,10,倍、,100,倍、,1000,倍,新授,？元,？元,每个,65,元,每个,6.5,元,说出下列各式的意义：,0.9 X 4,6.3 X 9,8.4 X 15,32.,3.,5,68,4.,224,X 5 =,6.,5,X 16 =,0.,23,X 4 =,056,1.,小数乘以整数,先要把被乘数扩大成,( ),数,然后按照,( ),的法则进行计算,最后看被乘数里有几位小数,就从积的,( ),边起,向,( ),数出几位点上小数点,.,整,整数乘法,右,左,练习,:,1.,计算下面各题,2.14 X 51,1.8 X 63,0.014 X 72,2.,不用计算,你能确定下面各题的积,是几位小数吗,?,0.3 X 3,0.89 X 19,14.87 X 2,0.01 X 17,14.4 X 828,1.125 X 235,0.75 X 4,12.5 X 80,3.,根据,21X15=315,在（）里填上,合适的数。,( ) X ( ) = ( ) X ( ) = 3.15,( ) X ( ) = ( ) X ( ) = 31. 5,( ) X ( ) = ( ) X ( ) = 3150,0.21,15,21,0.15,2.1,1.5,210,150,15,15,21,21,4.,发散练习,:,在下面的,( ),里填上合适的数,看谁填的最多。,0.48=,（ ）,X,（ ）,