第2课时小数的读法和写法小数的意义和性质4优翼www.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.com www.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.com认识小数的数位——十分位把一张正方形纸（平均分成10份）。问题：1.从这幅图上表示出分数，并改写成小数。2.你能表示出几个这样的小数？复习导入一 www.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.com出示例题情境2探索新知二 www.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.com研究数位的意义整数部分小数点小数部分12.3781.85.631.介绍个位及其计数单位，说一说它表示什么。探索新知二个位，计数单位是一，表示几个一。 www.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.com表示几个十分之一，是“十分位”。探索新知二研究数位的意义2.你能像这样说说其他数位表示什么吗？整数部分小数点小数部分12.3781.85.63个位，计数单位是一，表示几个一。 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www.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.com读小数时，先读整数部分，按整数的读法去读；再读小数点，小数点读作“点”；最后读小数部分，小数部分要依次读出每一位上的数字。（注意：整数部分是0的小数，整数部分就读零；小数部分有几个0就读出几个零）小数的写法：先写整数部分，按照整数的写法去写，如果整数部分是零，就直接写0；再在个位的右下角点小数点；最后依次写出小数部分每一位上的数字。课堂小结四 www.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.com课后练习五 www.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.com832课后练习五 www.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.com课后练习五 www.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.com2个十2个百分之一2个十分之一2个千分之一课后练习五 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www.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.comwww.youyi100.com（1）0.358；0.385；0.538；0.583；0.853；0.835（2）8.035；8.053；8.305；8.503；8.350；8.530（3）30.58；30.85；50.38；50.83；80.35；80.53课后练习五