信息窗三(分数加减混合运算).ppt

,R,五年级下册,3.,分数加减混合运算,第,1,课时 分数加减混合运算,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,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,情景导入,同学们，今天我们来了解一下国家级景区云梦森林公园的地貌。,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,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,探究新知,地貌类型,占公园面积的几分之几,乔木林,灌木林,草地,云梦森林公园地貌情况对比,1,2,3,10,1,5,你能提出哪些数学问题？,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,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,地貌类型,占公园面积的几分之几,乔木林,灌木林,草地,云梦森林公园地貌情况对比,1,2,3,10,1,5,森林部分,（,1,）森林部分比草地部分多几分之几？,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,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,你会算吗？,这是异分母分数的加减混合运算，得先通分。怎样通分好呢？,（,1,）森林部分比草地部分多几分之几？,这是分数加减混合运算，应该和整数加减混合运算一样，从左往右算就可以了。,+,-,=,3,10,1,5,1,2,_,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,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,+,-,3,10,1,5,1,2,=+,-,3,10,1,5,5,10,1,5,=,-,8,10,4,5,3,5,=,+,-,3,10,1,5,1,2,=+,-,3,10,2,10,5,10,2,10,=,-,8,10,6,10,=,3,5,3,5,=,小林的方法：,小萍的方法：,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,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,小林的方法是先把前两个数通分，计算出结果后再和第三个数通分，也就是分步通分计算的。,+,-,3,10,1,5,1,2,=+,-,3,10,1,5,5,10,1,5,=,-,8,10,4,5,3,5,=,小林的方法：,分步通分：,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,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,+,-,3,10,1,5,2,1,=+,-,3,10,2,10,5,10,2,10,=,-,8,10,6,10,=,3,5,3,5,=,小萍的方法：,一次通分：,小萍的方法是一次性把三个数都通分，然后再按照从左往右的顺序计算，比小林的方法相对要简便一些。,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,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,分数加减混合运算的运算顺序与整数加减混合运算的计算顺序相同。,三个分数是异分母分数，可以分步通分，也可以一次通分进行计算，但一次通分比较简便。,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,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,-,+,1,3,5,6,1,2,-,+,5,12,1,6,7,8,=,-,+,3,6,2,6,5,6,=+,2,6,2,6,4,6,=,=,-,+,10,24,4,24,21,24,=+,11,24,4,24,15,24,=,5,8,5,8,=,=,2,3,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,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,（,2,）森林和裸露地面降水转化情况对比,地貌类型,储存为,地下水,地表水,其他,森林,裸露地面,1,4,7,20,2,5,11,20,2,5,（）,（）,裸露地面储存的地下水占降水量的几分之几？,有几种列式方法？,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,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,-,-,11,20,2,5,1,8,20,=,-,9,20,1,20,=,1,20,=,-,（,+,）,11,20,1,8,20,=,-,19,20,1,=,-,-,11,20,20,20,8,20,两种方法有什么不同？,方法,1,方法,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,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,我们的方法有什么不同呢？,我用小括号了。,我是先求储存为地下水和其他一共占几分之几，再求储存为地下水占几分之几。,先求地表水和其他一共占几分之几，再求储存为地下水占几分之几。,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,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,分数加减混合运算与整数加减混合运算的顺序相同，也是按照从左往右的顺序计算，带有小括号的,先算小括号里面的，再算小括号外面的,。,你能说一说分数加减混合运算的运算顺序吗？,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,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,-,（,+,）,5,12,1,6,7,8,-,（,+,）,1,3,5,6,1,2,=,-,3+2,23,5,6,=0,=,-,5,6,5,6,7,24,=,=,-,（,+,）,10,24,4,24,21,24,=,-,21,24,14,24,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,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,巩固提升,1.,计算。,+,（,-,）,1,6,1,2,1,4,-,（,+,）,1,5,9,4,1,4,=+,6,-,4,46,1,2,7,12,=,=+,1,12,1,2,=+,6,12,1,12,=,-,5+,4,45,9,4,36,20,=,=,-,9,20,9,4,=,-,45,20,9,20,9,5,9,5,=,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,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,+,-,1,4,1,6,1,2,-,+,1,4,1,5,9,4,=+,-,3,12,2,12,6,12,=,-,9,12,2,12,=,7,12,=,-,+,5,20,4,20,45,20,=+,40,20,4,20,=,44,20,11,5,11,5,=,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,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,-,（,+,）,3,10,4,3,2,5,+,（,-,）,1,2,5,9,3,4,+,-,1,10,3,8,2,5,+,-,9,14,1,4,5,7,2.,计算,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,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,-,（,+,）,3,10,4,3,2,5,19,30,=,=,-,7,10,4,3,=,-,40,30,21,30,+,-,9,14,1,4,5,7,=+,-,7,28,18,28,20,28,18,28,=,-,27,28,9,28,=,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,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,+,（,-,）,1,2,5,9,3,4,29,36,=,=+,1,4,5,9,=+,20,36,9,36,+,-,1,10,3,8,2,5,3,40,=,=,-,19,40,16,40,=+,-,15,40,4,40,16,40,课后作业,1.,课本,P100,，第,2,、,3,、,4,题；,2.,完成练习册本课时的习题。,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,湖北山河律师事务所,