1、两位数减两位数（退位减）数学人教版 二年级上1.竖式计算。52-21=34-20=79-37=5 2-2 13 3 4-2 01 4 7 9-3 74 231 114 42复习导入复习导入情景导入情景导入851543我的妈妈在哪里？自主探究自主探究5136探究要求：探究要求：1.1.拿出小棒，小组同学合作，试着摆一摆。拿出小棒，小组同学合作，试着摆一摆。2.2.小组讨论，说一说是怎样想的。小组讨论，说一说是怎样想的。3.3.讨论完后安静坐好，举手汇报。讨论完后安静坐好，举手汇报。自主探究自主探究513615怎样列竖式？新知讲解新知讲解5 1 3 61 5114个位上1减6不够减，从十位退1，是
2、10，11减6得5。个位够不够减？不够减怎么办？513615退位点新知讲解新知讲解2650245 0 2 462从十位退1后，十位要算（）减（）。24个位上0减4不够减，从十位退1后，个位要算（）减（）。104个位够不够减？不够减怎么办？课堂练习课堂练习1.做一做。4 3 2 9411443297 2 2 7544572276 1 385586135 4 1 683385416笔算退位减法要注意什么？相同的数位要对齐；从个位减起；个位不够减，从十位退“1”当10再减；“退位点”提醒我们从十位减1。课堂练习课堂练习2.判断。（1）列竖式时，相同数位要对齐。（）（2）两位数相减，从个位减起。（）（
3、3）个位不够减，从十位退一。（）（4）两数相减，个位不够减，就将被减数的十位对齐减数的个位。（）课堂练习课堂练习3.看图列式计算。65个？个少17个65-17=6 5 1 78448课堂练习课堂练习4.我会判一判，正确的打，错的打，并改正过来。7 0-2 45 6（）6 2-1 95 3（）9 0-5 94 9（）xxx 7 0-2 44 6 6 2-1 94 3 9 0-5 93 15课堂练习课堂练习5.在方框里填上合适的数。4 1 8725 6 916 3 713 746拓展提高拓展提高想一想，填一填。4-28=()=()69课堂总结课堂总结 笔算两位数减两位数的退位减法时，个位不够减，从
4、十位退“1”当10再减；记住十位要减1。这节课你有什么收获？板书设计板书设计两位数减两位数（退位减）5 1 3 61 5114退位点513615作业布置作业布置教材21页第6题1、Genius only means hard-working all ones life.(Mendeleyer,Russian Chemist)天才只意味着终身不懈的努力。20.8.58.5.202011:0311:03:10Aug-2011:032、Our destiny offers not only the cup of despair,but the chalice of opportunity.(Rich
5、ard Nixon,American President)命运给予我们的不是失望之酒，而是机会之杯。二二年八月五日2020年8月5日星期三3、Patience is bitter,but its fruit is sweet.(Jean Jacques Rousseau,French thinker)忍耐是痛苦的，但它的果实是甜蜜的。11:038.5.202011:038.5.202011:0311:03:108.5.202011:038.5.20204、All that you do,do with your might;things done by halves are never don
6、e right.-R.H.Stoddard,American poet做一切事都应尽力而为，半途而废永远不行8.5.20208.5.202011:0311:0311:03:1011:03:105、You have to believe in yourself.Thats the secret of success.-Charles Chaplin人必须相信自己，这是成功的秘诀。-Wednesday,August 5,2020August 20Wednesday,August 5,20208/5/20206、Almost any situation-good or bad-is affected
7、 by the attitude we bring to.-Lucius Annaus Seneca差不多任何一种处境-无论是好是坏-都受到我们对待处境态度的影响。11时3分11时3分5-Aug-208.5.20207、Although the world is full of suffering,it is full also of the overcoming of it.-Hellen Keller,American writer虽然世界多苦难，但是苦难总是能战胜的。20.8.520.8.520.8.5。2020年8月5日星期三二二年八月五日8、For man is man and ma
8、ster of his fate.-Tennyson人就是人，是自己命运的主人11:0311:03:108.5.2020Wednesday,August 5,20209、When success comes in the door,it seems,love often goes out the window.-Joyce Brothers成功来到门前时，爱情往往就走出了窗外。11:038.5.202011:038.5.202011:0311:03:108.5.202011:038.5.202010、Life is measured by thought and action,not by t
9、ime.Lubbock 衡量生命的尺度是思想和行为，而不是时间。8.5.20208.5.202011:0311:0311:03:1011:03:1011、To make a lasting marriage we have to overcome self-centeredness.要使婚姻长久，就需克服自我中心意识。Wednesday,August 5,2020August 20Wednesday,August 5,20208/5/202012、Treat other people as you hope they will treat you.你希望别人如何对待你，你就如何对待别人。11时
10、3分11时3分5-Aug-208.5.202013、To do whatever needs to be done to preserve this last and greatest bastion of freedom.(Ronald Reagan,American President)为了保住这最后的、最伟大的自由堡垒，我们必须尽我们所能。20.8.520.8.5Wednesday,August 5,202014、Where there is a will,there is a way.(Thomas Edison,American inventor)有志者，事竟成。11:01:1911
11、:01:1911:018/5/2020 11:01:19 AM15、Every man is the master of his own fortune.-Richard Steele每个人都主宰自己的命运。20.8.511:01:1911:01Aug-205-Aug-2016、As selfishness and complaint cloud the mind,so love with its joy clears and sharpens the vision.-Helen Keller自私和抱怨是心灵的阴暗，愉快的爱则使视野明朗开阔。11:01:1911:01:1911:01Wedne
12、sday,August 5,202017、Do not,for one repulse,give up the purpose that you resolved to effect.-Willian Shakespeare,British dramatist不要只因一次失败，就放弃你原来决心想达到的目的。20.8.520.8.511:01:1911:01:19August 5,202018、There is no absolute success in the world,only constant progress.世界上的事没有绝对成功，只有不断的进步。2020年8月5日星期三上午11时
13、1分19秒11:01:1920.8.519、Nothing is more fatal to happiness than the remembrance of happiness.没有什么比回忆幸福更令人痛苦的了。2020年8月上午11时1分20.8.511:01August 5,202020、No man is happy who does not think himself so.Publilius Syrus认为自己不幸福的人就不会幸福。2020年8月5日星期三11时1分19秒11:01:195 August 202021、The emperor treats talent as tools,using their strongpoint to his advantage.君子用人如器，各取所长。上午11时1分19秒上午11时1分11:01:1920.8.5谢谢观看THE END
