小数产生与意义课件

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,*,小数的产生和意义,长塘里小学,:,余少文,人们在测量和计算时,往往不能正好得到整数的结果,.,这时常用,小数,来表示。,小数是如何产生的？,0,1,分米,2,3,4,5,6 7,8,9,10,1,米,0.1,米,研究成果一,把一米平均分成,10,份，每份是（）分米,0.3,米,0.7,米,1,10,1,米,10,3,米,10,7,米,1,厘米,2,3,4,5,6,7,8,9,0.01,米,研究成果二：,把一米平均分成,100,份，每份是（）厘米,0.03,米,1,0.06,米,100,1,米,100,3,米,100,6,米,1,厘米,0.001,米,研究成果三：,把一米平均分成,1000,份，每份是（）毫米,0.006,米,1,1,1000,米,6,1000,米,13,1000,米,0.013,米,分母是,10,、,100,、,1000,的分数可以用小数来表示。小数的计数单位是十分之一、百分之一、千分之一,分别写作,0.1,、,0.01,、,0.001,12,103,1,1,100,1000,100000,10000,0.103,0.0001,0.12,0.00001,第一关,找朋友,第二关,0.7,里面有,(),个十分之一。,7,0.04,里面有,(),个百分之一。,4,0.211,里面有,(),个千分之一。,211,3,个,(),是,0.03,。,0.01,15,个,(),是,0.015,。,0.001,8,个,(),是,0.8,。,0.1,0.9,里面有,(),个,0.1,。再添上,(),个,0.1,就是,1.,9,1,0.09,里面有,(),个,0.01,。再添上,(),个,0.01,就是,0.1,。,9,1,第三关,(),个,0.1,是,1,。,10,(),个,0.01,是,0.1,。,(),个,0.001,是,0.01,。,10,10,每相邻两个计数单位间的进率是,10,。,相邻,挑战一,判断,1,毫米写成小数是,0.01(),6,元,5,分,=6.05,元,(),0.32,里面有,32,个,0.1(),挑战二,选择,2,毫米写成小数是,(),(1)0.002,米,(2)0.002,(3)0.002,分米,(1),(4)0.02,米,0.39,表示,(),(1)0.39,米,(2)39,个,0.01,(3)39,个,0.1,(4)39,个百分之一,(2),(4),0.1,比,0.01,多,(),个,0.01,(1)1,(2)9,(3)0.9,(4)10,(2),