小数的扩大与缩小(课堂PPT).ppt

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,*,小数的扩大与缩小,人教版,数学,四年级下册,1,（,1,）把,0.07,分别扩大到原来的,10,倍、,100,倍、,1000,倍，各是多少？,0.07,扩大到原来的,10,倍，就是乘,10,。,0.0710,0.7,。,把,0.07,扩大到原来的,10,倍，就是把小数点向右移动一位，得,0.7,。,例,2,2,（,1,）把,0.07,分别扩大到原来的,10,倍、,100,倍、,1000,倍，各是多少？,0.07,扩大到原来的,100,倍，就是乘,100,。,0.07100,7,。,把,0.07,扩大到原来的100,倍，就是把小数点向右移动两位，得,7,。,例,2,3,（,1,）把,0.07,分别扩大到原来的,10,倍、,100,倍、,1000,倍，各是多少？,0.07,扩大到原来的,1000,倍，就是乘,1000,。,0.071000,70,。,把,0.07,扩大到原来的,1000,倍，就是把小数点向右移动三位，得,70,。,例,2,4,把下面的数分别扩大到原来的,10,倍、,100,倍、,1000,倍。,4.8 0.735 12.6,4.810,48 4.8100,480 4.81000,4800,0.73510,7.35 0.735100,73.5 0.7351000,735,12.610126 12.6100,1260 12.61000,12600,P44,做一做第,1,题,5,（,2,）把,3.2,分别缩小到原来的 、，各是多少？,1,10,1,100,1,1000,3.2,缩小到原来的 ，就是除以,10,。,3.210,0.32,。,1,10,3.2,缩小到原来的 ，就是把小数点向左移动一位，得,0.32,。,1,10,例,2,6,（,2,）把,3.2,分别缩小到原来的 、，各是多少？,1,10,1,100,1,1000,3.2,缩小到原来的 ，就是把小数点向左移动两位，得,0.032,。,1,100,例,2,7,（,2,）把,3.2,分别缩小到原来的 、，各是多少？,1,10,1,100,1,1000,3.2,缩小到原来的 ，就是除以,1000,。,3.21000,0.0032,。,1,1000,3.2,缩小到原来的 ，就是把小数点向左移动三位，得,0.0032,。,1,1000,例,2,8,93.510,9.35 93.5100,0.935 93.51000,0.0935,50010,50,500100,5 5001000,0.5,999910,999.9 9999100,99.99 99991000,9.999,把下面的数分别缩小到原来的 、。,9.35 500 9999,1,10,1,100,1,1000,P44,做一做第,2,题,9,商品,单价,/元,数量,10,100,1000,曲奇饼,2.63,练习本,0.45,QQ,糖,3.89,26.3,263,2630,4.5,45,450,38.9,389,3890,在下表中填出每种商品的总价。,P46,第,2,题,10,10=,10=,100=,100=,48.3,483,0.72910,72.9,（）,7290,（）,0.0729,（）,7.29,10,0.483,4830,4.83,1000,100,P46,第,4,题 填一填,11,1.0.07,里面有（）个,0.007,。,A.63 B.10 C.100,2.1,是由,100,个（）组成的。,A.0.01 B.0.1 C.0.001,3.,把,4.03,扩大到原来的（）倍是,4030,。,A.100 B.10000 C.1000,练一练,B,A,C,12,152.7,扩大到原来,10,倍，再把小数点向左移动三位，再扩大到原来的,1000,倍，然后乘,100,，再除以,1000,，最后小数点向左移动四位，再向右移动两位，这个数变成（）。,练一练,1.527,13,再见,14,