1、第 1 课 时 小数的意义和读写,五年级同学身高和跳远统计表,你认识这些数吗?,创设情境,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。,新知探究,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,新知探究,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,新知探究,1,在括号里填上合适的数,先填一填,再读一读。,0.01米,(
2、)米,( )米,7,100,0.07,11,100,0.11,新知探究,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?,巩固练习,1,把1米长的直尺,平均分成1000份,每份的长度是多少?,1毫米是1米的几分之几?是多少厘米?,1毫米,米( )米,1,1000,0.001,0.001读作:零点零零一,新知探究,1,40毫米、105毫米分别改写成用米作单位的分数和小数。,40毫米,米( )米,40,1000,0.040,105毫米,米( )米,105,1000,0.105,0.0
3、40读作:零点零四零,0.105读作:零点一零五,新知探究,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。,3,1000,0.003,86,1000,0.086,新知探究,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,课堂小结,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。,课堂小结,1分是,1,元,写成小数是( )元。,5分是,元,写成小数是( )元。,7角3分是,元,写成小数是( )元。,100,0.01,5,100,0.05,73,100,0.73,试一试,下面每个图形都表示整数“1”,先涂色表示它上面的小数,再填空。,0.7,0.43,0.009,练一练,