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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,第三级,第四级,第五级,*,小数点位置向右移动的规律和应用,冀教版数学五年级上册第二单元,教学目标,1,、结合具体事例,经历自主探索小数点位置向右移动的规律及应用规律进行计算的过程,理解并掌握小数点向右移动的规律。,2,、能运用规律口算小数乘,10,、,100,、,1000,的乘法,能把小数表示的单位名数改写成较小单位的数或复名数。,3,、积极参加数学活动,获得用已有知识解决问题的成功体验,培养判断、归纳能力。,1,枚纽扣,5,分钱,,10,枚纽扣多少元?,100,枚、,1000,枚呢?,想一想:怎样计算呢?,1,枚纽扣,5,分,,,10,枚纽扣共,5,角,,5,分可以写成,0.05,元,,5,角可以写成,0.5,元,。,0.05,10,0.5,(元),1,枚纽扣,5,分钱,,10,枚纽扣多少元?,乘法算式:,答:,10,枚纽扣,0.5,元。,1,枚纽扣,5,分,,,100,枚纽扣共,5,元,。,0.05,100,5,(元),1,枚纽扣,5,分钱,,100,枚纽扣多少元?,乘法算式:,答:,100,枚纽扣,5,元。,1,枚纽扣,5,分,,,1000,枚纽扣共,50,元,。,0.05,1000,50,(元),1,枚纽扣,5,分钱,,1000,枚纽扣多少元?,乘法算式:,答:,1000,枚纽扣,50,元。,观察下面几个算式,你发现了什么?,0.05,10,0.5,(元),0.05,100,5,(元),0.05,1000,50,(元),小数点位置向右移动的规律,一个数扩大到原来的,10,倍,一个数扩大到原来的,100,倍,一个数扩大到原来的,1000,倍,小数点向右移动一位,小数点向右移动两位,小数点向右移动三位,试一试,把,3.87,分别扩大到原来的,10,倍、,100,倍、,1000,倍,各是多少?,3.87,10=,38.7,3.87,1000,,把,3.87,的小数点向右移动三位,位数不够,怎么办?,3.87,100=,387,3.87,3.870,3.87,1000,3.870,1000,3870,位数不够时,要用,0,补足。,把写字台的长和宽改写成以厘米为单位的数?,1,米是,100,厘米,,0.3,米是,30,厘米。,把,1.3,米改写成以厘米为单位的数是,100,厘米加,30,厘米,是,130,厘米。,方法一:,1.3,米,100,厘米,30,厘米,130,厘米,把写字台的长和宽改写成以厘米为单位的数?,米和厘米之间的进率是,100,。,把米改写成以厘米为单位的数时,直接乘进率,100,,,1.3,乘,100,,把,1.3,的小数点向右移动两位是,130,。,方法二:,1.3,100,130,(厘米),把写字台的长和宽改写成以厘米为单位的数?,想一想:,0.65m,_cm,0.65,100,65,(厘米),65,练一练,1.,填表。,1835,1330,630,4.2,2.,320,1960,4,85,6,90,0.32,吨()千克,1.96,升()毫升,4.85,米()米()厘米,6.09,吨()吨()千克,3.,35,7.86,960,47.9,70,17600,3.5,10,0.786,10,9.6,100,0.479,100,0.07,1000,17.6,1000,小学数学课件,灿若寒星整理制作,
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