第1课时分数和小数的互化(1).ppt

1、状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,R五年级下册,第1课时 分数和小数的互化（1）,6.分数和小数的互化,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,1.说出下列各分数的分数单位和有几个这样的单位。,引入新课,2.填空。 (1)0.6表示( )分之( )。0.09表示( )分之( )。 (2)0.5表示( )分之( )，写作 。 (3)0.006里面有( )个千分之一，它表示( )分之(

2、)，写成分数是 。,十,六,百,九,十,五,10,5,6,千,六,1000,6,1,把一条3m长的绳子平均分成10段，每段长多少米？,310=0.3（m）,310= （m）,如何列式计算？,探究新知,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,0.3m和 m有什么关系？,310=0.3（m）,310= （m）,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,把小数化成分数时,原来有几位小数,就在1的后

3、面写几个0作分母,原来的小数去掉小数点作分子。,小数化成分数的方法：,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,问题：每段长多少米？,35=0.6（m）,35= （m）,把一条3m长的绳子平均分成5段。,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,35=0.6（m）,35= （m）,3,5,小数化成分数，需要注意什么？,需要化简的分数，要化简成最简分数。,状元成才路,状元成才路,状元成才路,状元

4、成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,100,100,123,1000,6,25,做一做,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,1.填空,把0.25化成分数时，因为0.25是（ ）小数，所以就在1后面写（ ）个0作（ ），把0.25去掉小数点作（ ），最后是（ ）。,两位,2,分母,分子,达标检测,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才

5、路,状元成才路,2.分别用小数和分数表示下面每个图形的阴影部分。,小数:( ) 小数:( ) 分数:( ) 分数:( ),0.07,0.2,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,3.哪两只手套是一双，连一连。,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,0.65 = （ ）,1.07 = （ ）,0.5 = （ ）,4.下面的小数化分数是否正确？,状元成才路,状元成才路,状元成才路,状元成才

6、路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,0.7 6.13 0.08 0.65 1.075,0.7=,7,10,6.13=,100,13,0.08=,8,100,2,25,=,25,2,0.65=,100,65,=,13,20,20,13,1.075=,1000,1075,215,200,5、把下面的小数化成分数。,6,43,40,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,小数表示十分之几、百分之几、千分之几的数,所以可以直接写成分母是10,100,1000的分数,再化简。,课堂小结,1. 课本练习十九，第1、2、3题； 2. 完成练习册本课时的习题。,课后作业,声 明 本文件仅用于个人学习、研究或欣赏，以及其他非商业性或非盈利性用途，但同时应遵守著作权法及其他相关法律的规定，不得侵犯本司及相关权利人的合法权利。 除此以外，将本文件任何内容用于其他用途时，应获得授权，如发现未经授权用于商业或盈利用途将追加侵权者的法律责任。 武汉天成贵龙文化传播有限公司 湖