教育专题：《口算除法》教学课件

单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,*,除数是两位数的除法,口算除法,一、复习导入，揭示课题,20,3,7,50,6,3,20,5,4,9,8,60,24,6,8,2,12,3,42,6,90,3,3000,5,口算下面各题。,60,350,18,100,36,480,4,4,4,7,30,600,看谁都能算正确。,二、探究新知,有,80,面彩旗，每班分,20,面，可以分给几个班？,80,20,你知道了什么？求什么？,知道了有,80,面彩旗，每班要分,20,面，求能分给几个班，,就是求,80,里面有几个,20,，应该用除法解答,。,你会口算吗？,二、探究新知,4(,个,),80,20,8,2,4,，,80,20,4,。,(,),个,20,是,80,，,80,20,(,),。,4,4,4,0,2,0,6,0,2,0,9,0,3,0,1,0,0,2,0,2,5,3,3,83,80,，,80,20,4,，所以,83,20,4,。,19,20,，,80,20,4,，所以,80,19,4,。,想一想：,83,20,80,19,4,(,80,),4,(,20,),二、探究新知,你是怎样计算的？和同学们交流一下。,42,20,62,20,93,30,103,20,2,5,3,3,150,50,15,5,(),，,150,50,(),。,(),个,50,是,150,，,150,50,(),。,3,3,3,3,3,二、探究新知,这道题应该怎么算？,83,20,4,试着想一想，该怎么估算。,(,80,),80,19,4,(,20,),122,30,120,28,4,(,120,),4,(,30,),用,四舍五入法,把被除数和除数都看作与它接近的整十、整百或几百几十来估算。,二、探究新知,180,30,240,40,210,30,420,60,6,6,7,7,184,30,240,37,210,29,420,62,6,6,7,7,三、知识应用,练习十二,30,2,40,3,60,30,120,40,2,60,3,120,3,240,5,450,1.,80,3,90,5,240,80,450,90,30,180,270,30,80,200,280,40,1,6,9,2,5,7,2.,口算下面各题，看看谁能全对。,240,30,8,（包）,答：要捆,8,包。,同学们，题目中已知的是什么？要求的是什么？,看完这本书大约需要几个月？,