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第,1,课时 小数的意义和读写法,第三单元 小数的意义和性质,旧知回顾,五年级同学身高和跳远统计表,姓 名,身高,/m,跳远,/m,李明,1.3,2.5,刘丹,1.54,2.57,许达,1.47,2.83,白洁,1.4,2.6,你认识这些数吗?,新知讲解,填一填。,1,分米,米( )米,3,分米,米( )米,1,1,分米是几分之几米?写成小数是多少?,1,10,0.1,3,10,0.3,一位小数表示十分之几。,新知讲解,1,1,厘米,米( )米,1,100,0.01,1,厘米是,1,米的几分之几?是几分之几米?写成小数是多少?,0.01,读作:,零点零一,新知讲解,1,4,厘米,米( )米,4,100,0.04,0.04,读作:,零点零四,12,厘米,米( )米,12,100,0.12,0.12,读作:,零点一二,4,厘,米、,12,厘米各是,1,米的几分之几?各是几分之几米?,新知讲解,1,在括号里填上合适的数,先填一填,再读一读。,0.01,( )米,( )米,7,100,0.07,11,100,0.11,新知讲解,1,0.01,、,0.04,、,0.12,、,0.07,、,0.11,这几个小数有什么共同点?,两位小数表示百分之几。,什么样的分数可以写成三位小数?三位小数表示的应该是怎样的分数?,新知讲解,1,1,毫米等于几分之几米?,40,毫米、,105,毫米呢?,1,毫米,米( )米,1,1000,0.001,0.001,读作:,零点零零一,40,毫米,米( )米,1000,0.040,105,毫米,米( )米,1000,0.105,40,105,0.040,读作:,零点零四零,0.105,读作:,零点一零五,新知讲解,1,0.001,、,0.040,、,0.105,这几个小数有什么共同点?,三位小数表示千分之几。,3,1000,0.003,3,毫米,米( )米,86,毫米,米( )米,86,1000,0.086,归纳总结,分母是,10,、,100,、,100,的分数都可以用小数表示。,一位小数表示十分之几,,,两位小数表示百分之几,,,三位小数表示千分之几,巩固练习,说一说下面小数表示的意义,再读一读。,0.867,0.45,0.3,0.010,零点八六七,零点四五,零点三,零点零一零,小数点之前的按照整数的,读法读,;小数点读,“,点,”,;小数点之后的部分,顺次读出每个数字,。,谢 谢 观 看!,
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