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单击此处编辑母版标题样式,单击此处编辑母版文本样式,二级,三级,四级,五级,*,*,第,3,课时 几百几十数加减整十数(进位加、退位减),六 三位数加减三位数,JJ,二年级下册,课后作业,探索新知,课堂小结,当堂检测,几百几十数加整十数和相应的减法,1,课堂探究点,2,课时流程,探究点 几百几十数加整十数和相应的减法,150,+,80=,(棵),230,(,1,)一共多少棵果树?,1,150,+,80,=,(棵),230,130,+,100,=,(棵),130,50,+,80,=,(棵),230,150,80,=,(棵),150,80,=,(棵),70,50,+,20,=,(棵),100,80,=,(棵),20,70,70,(,2,)苹果树比梨树多多少棵?,1,填一填。,160,90,(,),想,1,:,想,2,:,小试牛刀,(选题源,典中点,),16,250,250,250,9,60,150,十,十,25,十,230,80,460,70,540,60,70,260,330,310,530,600,2,口算下面各题。,250,70,(,),3,填一填。,180,30,想,1,:,(,),个十减去,(,),个十是,(,),个,(,),,是,(,),。,想,2,:,180,180,25,7,18,十,360,90,420,40,280,90,160,80,750,70,210,60,4,口算下面各题。,80,270,380,190,680,150,口算几百几十加减整十数(进位加、退位减)时:,1,可以把三位数看作以“十”为单位的数,再计算。,2,也可以把几百几十拆分成整百数和整十数再计算。,归纳总结:,(讲解源于,典中点,),夯实基础,(选题源于教材,P54,练一练),920,350,640,800,170,380,1,720+200=300+50=240+400=,890,90,=,970,800=80+300=,每张卡片上两个数的和是多少?差是多少?(口答),3,(,1,)一头牛和一只羊一共重多少千克?,(,2,)一头牛比一只羊重多少千克?,(,1,),330,+,80,=,410,(千克),答:一头牛和一只羊一共重,410,千克。,(,2,),330,80,=,250,(千克),答:一头牛比一只羊重,250,千克。,4.,李阿姨购进,340,箱饮料,卖了一个星期后,还剩,60,箱。卖了多少箱?,340,60,=,280,(箱),答:卖了,280,箱,。,5.,张叔叔的养鸡场,21,天孵出,460,只小鸡。张叔叔的养鸡场孵小鸡一共用了多少个鸡蛋?,460,+,90,=,550,(个),答:,张叔叔的养鸡场孵小鸡一共用了,550,个鸡蛋,。,6.,摘桃子。,40,500,540,220,60,280,210,700,910,300,80,380,70,140,210,190,60,250,680,40,640,500,400,100,660,60,600,370,200,170,830,80,750,720,50,670,450,(,),80(,),60,320,(,),60,35030,(,),510,5,在括号里填上合适的数。,辨析:求减数用减法,求加数用减法,求被减数用加法。,易错辨析,(选题源于,典中点,),370,260,410,480,作 业,请完成,典中点,的“应用提升练”和“思维拓展练”习题,具体内容见习题课件。,Thank you!,
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