在日常学习、工作或生活中,大家总少不了接触作文或者范文吧,通过文章可以把我们那些零零散散的思想,聚集在一块。大家想知道怎么样才能写一篇比较优质的范文吗?这里我整理了一些优秀的范文,希望对大家有所帮助,下面我们就来了解一下吧。
加法交换律教学方法篇一
教材p28页例1,p30页练习相关习题。
教学目标
1、知识与技能:
结合具体的情境,引导学生认识和理解加法交换律的含义。
2、过程与方法:能用字母式子表示加法交换律,初步学会应用加法交换律进行一些简便运算。
3、情感态度与价值观:
①体验自主探索、合作交流,感受成功的愉悦,树立学习数学的自信心,发展对数学的积极情感。
②培养学生观察,比较,抽象,概括的初步思维能力。
教学重点
认识和理解加法交换律的含义。
教学难点
引导学生抽象,概括加法交换律。
教学用具
多媒体课件。
教学过程
(一)出示自学提纲
自学提纲(教材p28页例1,并完成自学提纲问题,将不会的问题做标注)
1、根据例1情境图中信息列出算式。
2、用你喜欢的方法尝试计算
3、同桌交流自己的算法
4、教师板书出学生的算式及答案
40+56=96(千米) 56+40=96(千米)
5、对比上面的两道算式,你发现了什么?用自己的话说一说。
(二)学生自学(学生对照自学提纲,自学教材p28页例1,并完成自学提纲问题,将不会的问题做标注)
(学生自学,教师在不干扰学生的前提下巡回指导,发现共性问题,以掌握学生学情)
(三)自学检测
1、填空
387+425=( )+ 387 525+( )=137+ 525
300+600=( )+( ) ( )+65=( )+35
甲数+乙数=( )+( ) 偶数+( )=奇数+( )
2、连线
56+68 50+b
b+50 68+56
(一)小组互探(自学中遇到不会的问题,同桌或学习小组内互相交流。把小组也解决不了的问题记好,到学生质疑时提出,让其他学习小组或教师讲解。)
(引导学生正确地计算,鼓励学生分工合作,探索交流,教师巡回辅导,发现、收集学生存在的问题)
(二)师生互探
1、解答各小组自学中遇到不会的问题。
(1)让学生提出不会的问题,并让学生解决。
(2)教师引导学生解决学生还遗留的问题。
(3)如何用字母表示加法交换律和结合律?
(4)用字母表示这些运算定律有什么优点?
2、教师有针对性地请不同做法的同学汇报自己的解题思路与方法。
1、填空题。
(1)360+482=( )+ 360 128+275=125+( )
(2)( )+ 78 =78 +149 133+( )=125+133
2、连线。
38+175 47+b
b+47 175+38
3、简便计算下面各题。
89+91+11 268+147+32
课堂小结:谈谈你有什么收获?有什么感受?还有问题吗?(学生总结不完整的地方,教师要适当补充总结)
(一)出示检测题(1—2题必做,3题选做,4题思考题)
1、根据加法交换律填空。
(1)450+320=( )+ 450 65+95=95+( )
(2)( )+ 100 =100+150 250+( )=125+( )
2、下面的哪些算式符合加法交换律。
(1)84 + c = b + 84
(2)10 + 20 + 30 + 40 =10 + (20 + 30) + 40
3、简便计算。
81+78+19 679+132+121
(二)堂清反馈:
作业布置
教材p30页习题。
板书设计
加法交换律
40+56=96(千米) 56+40 =96(千米)
a+b = b+a
加法交换律教学方法篇二
1、知识与技能:①结合具体的情境,引导学生认识和理解结合律的含义。
2、过程与方法:能用字母式子表示加法结合律,初步学会应用加法结合律进行一些简便运算。
3、情感态度与价值观:①体验自主探索、合作交流,感受成功的愉悦,树立学习数学的自信心,发展对数学的积极情感。②培养学生观察,比较,抽象,概括的初步思维能力。
认识和理解加法结合律的含义。
引导学生抽象,概括加法结合律。
多媒体课件。
一、自主学习
(一)出示自学提纲
自学提纲(p29页例2并完成自学提纲问题,将不会的问题做标注)
1、根据例2情境图中信息列出算式。
2、用你喜欢的方法尝试计算
3、同桌交流自己的算法
4、教师板书出学生的算式及答案
88+104+96 88+(104+96)
=192+96 =88+200
=288 =288
5、对比上面的两道算式,你发现了什么?用自己的话说一说。
(二)学生自学(学生对照自学提纲,自学教材p29页例2,并完成自学提纲问题,将不会的问题做标注)
(学生自学,教师在不干扰学生的前提下巡回指导,发现共性问题,以掌握学生学情)
(三)自学检测
1、填空
387+425=( )+ 387 525+( )=137+ 525
300+600=( )+( ) ( )+65=( )+35
2、连线
56+68 150+(25+75)
150+25+75 50+b
b+50 68+56
a+b+100 a+(b+100 )
三、合作探究
(一)小组互探(自学中遇到不会的问题,同桌或学习小组内互相交流。把小组也解决不了的问题记好,到学生质疑时提出,让其他学习小组或教师讲解。)
(引导学生正确地计算,鼓励学生分工合作,探索交流,教师巡回辅导,发现、收集学生存在的问题)
(二)师生互探
1、解答各小组自学中遇到不会的问题。
(1)让学生提出不会的问题,并让学生解决。
(2)教师引导学生解决学生还遗留的问题。
(3)如何用字母表示加法交换律和结合律?
(4)用字母表示这些运算定律有什么优点?
2、教师有针对性地请不同做法的同学汇报自己的解题思路与方法。
四、达标训练(1--3题必做,4题选做,5题思考题)
1、根据加法结合律填空题。
(1)78+25+22 =78 +( )+25
(2)376+175+25=376 +( + )
2、连线。
147+(72+28) a+(b+100 )
a+b+100 147+72+28
3、简便计算下面各题。
52+27+73 285+15+77+23
课堂小结:谈谈你有什么收获?有什么感受?还有问题吗?(学生总结不完整的地方,教师要适当补充总结)
五、堂清检测
(一)出示检测题
1、根椐加法的运算定律填空
(1)450+320=( )+ 450 65+95=95+( )
(2)( )+ 100 =100+150 250+( )=125+250
(3)78+25+22 =(78 + )+( )
(4)495+125+75=495 +( + )
2、下面的哪些算式符合加法结合律,哪些算式符合加法交换律。
(1)a + ( 30+9 )=a+ 30+9
(2)15+ ( 7+b )= (15 + 7 )+b
(3)10 + 20 + 30 + 40 =10 + (20 + 30) + 40
3、连线。
87+22+78 (79+83)+17
498+125+75 498+(125+75)
(138+136)+162 87+(22+78 )
79+(83+17) 138+136+162
4、简便计算。
98+72+28 215+85+73+27
(二)堂清反馈:
作业布置
加法交换律教学方法篇三
青岛版小学数学四年级下册第一单元信息窗三13页至14页的`内容。
1.让学生经历探索加法运算律的过程,理解并掌握加法交换律和结合律,会用字母来表示。
2.在探索运算律的过程中,发展学生的观察、比较、抽象、概括能力,培养学生的符号感。
3.让学生在数学学习过程中获得探究的乐趣、成功的喜悦,进一步增强对数学学习的兴趣和信心。
4.初步形成独立思考、合作交流的意识和习惯。
理解掌握加法的交换律和结合律,并会用字母表示他们。
引导学生通过讨论,计算从而自己发现并总结出加法交换律、加法结合律的过程。
课件、投影仪、卡片
一、拟定导学提纲,自主预习
(一)创设情境
1.谈话:同学们,长江,黄河就像两条长龙盘卧在中国大地,特别是黄河被称为我们的“母亲河”。这几天我们一直在学习有关黄河的知识,了解到了许多有关黄河的信息,除了我们学过的,你还了解到那些有关黄河的知识?(学生根据课前调查回答)想不想再多了解一些?
课件展示情境录像:(课件展示的关键是让学生从中知道黄河流域的小知识,例如上游:青藏高原黄土高原内蒙古高原中游:黄土高原下游:华北平原等小知识)最后大屏幕定格在信息窗三的情境图。
以上展示在大家面前的就是黄河流域图。教师板书:黄河流域
请同学们仔细观察,你能获得了哪些数学信息?
学生观察汇报,
生汇报:根据黄河流域图我了解到黄河分为上游、中游和下游(1、黄河上游长3472千米,中游长1206千米,下游长786千米;2、黄河上游流域面积是39万平方千米,中游是34万平方千米,下游是2万平方千米;)
教师适时板书相应的信息条件。
2.你能根据这些信息提出哪些数学问题呢?学生口答。教师板书出问题。
问题(1)黄河流域的面积是多少万平方千米?
问题(2)黄河全长多少千米?
(二)出示学习目标
同学们提出了这么多有价值的问题,那么今天我们将解决那些问题呢?请看本节课的学习目标:
1.让学生经历探索加法运算律的过程,理解并掌握加法交换律和结合律,会用字母来表示,能够运用所学的运算定律进行简算。
2.在探索运算律的过程中,发展学生的观察、比较、抽象、概括能力,培养学生的符号感。
(三)出示自学指导
为了能够更好地解决今天的学习目标,老师给大家提供了一些指导意见,请看自学指导。
(自学指导:请同学们认真看教科书第13—14页的信息窗3的第一个红点和小电脑的内容,重点看解决问题的过程,思考:(1)怎样解答同学们提出的问题?哪种方法简单?(2)什么是加法的结合律?怎样用字母式表示?(3)什么是加法交换律?怎样用字母式表示?
(5分钟后,比一比谁汇报得最清楚。)
(四)学生自学
师:下面请同学们根据“自学指导”开始自学,比一比谁看书最认真,谁自学效果最好!(师目光巡视每一个学生,特别要关注特困生。)
二、汇报交流,评价质疑
(一)调查
师:看完的同学请举手?
(二)全班汇报
1.问题一:黄河流域的面积是多少万平方千米?
学生在列式解答时,可能会出现两种情况:
(1)39+34+2和34+2+39
(2)(39+34)+2和39+(34+2)。
2.问题二:黄河全长多少千米?
学生可能出的情况:
(1)、3470+1210+790和1210+790+3470
(2)(3470+1210)+790和3470+(1210+790)。
今天我们要学的知识就在这两组算式中。
(设计意图:充分运用教材情境图,引导学生获取信息,提出加法问题。在此基础上让学生列出算式。通过这两组算式学习今天的新知识,为下面学习埋下了伏笔。学生会马上把精力投入到这两个算式的研究中,激发了学生探究的兴趣。)
3.观察、比较、发现规律
(1)观察这些算式,你们发现了什么?
生汇报:每组算式运算的数相同,运算的结果相同,运算的顺序不同。
例如:
(39+34)+2=39+(34+2)
(3470+1210)+790=3470+(1210+790)。
(2)是不是所有的三个数相加都符合这些规律呢?举例验证一下吧:(每个学生在练习本上写出几组这样的算式,看结果怎样)
生汇报:
(35+63)+15=35+(63+15)
(325+82)+18=325+(82+18)…
(3)把你的发现告诉大家?(将学生的举例用实物投影展示)
(三个数相加时,先把前两个数相加,或先把后两个数相加,和不变。)
师指出这条规律叫做加法结合律。
(4)你能用你喜欢的方法表示这加法结合律吗?
学生用各种符号、字母表示这个运算定律。最终教师指出,在数学上,我们统一用a、b、c来表示三个加数,因此加法结合律可以写作(a+b)+c=a+(b+c)。学生齐读,教师板书在黑板上
小结:刚才我们通过解决两个问题发现并归纳出了加法结和律。
(设计意图:本环节经历了猜测—举例—验证—得出结论的过程,无形之中培养了学生一种数学思想。)
4.学法迁移,探索加法交换律。
那么,加法运算中还有其他的规律吗?想不想知道?我们先来做个游戏吧。
(1)游戏:找朋友。
在每个小组中都有一个算式卡片,请同学们小组合作,仔细想一想,算一算,它应该是屏幕上哪个算式的好朋友?为什么?
(2)同学们真棒,很快就为自己的算式找到了合适的朋友,还有谁的算式没有找到朋友?你能根据刚才同学们的方法给他介绍一个合适的好朋友吗?
加法交换律教学方法篇四
设计理念:生活经验是小学生学习数学的宝贵财富,也是他们进行数学探索的基础。教师应充分利用学生已有的生活经验,让他们在此基础上实现对数学的再创造,切实体验数学与生活的联系,经历数学知识发生、发展和形成的过程,提高学生应用数学解决实际问题的能力。
教材分析:教材从情境引出例题,帮助学生体会运算定律的现实背景,让学生借助解决实际问题,进一步体会和认识加法交换律,使学生经历由个别到一般,由具体到抽象的认知过程,引导学生由感性认识上升到一定的理性认识。
教学目标:探索和理解加法交换律,并能够用字母来表示加法交换律;经历探索运算定律过程,通过对实际问题的解决,进行比较和分析,发现并概括出加法交换律;在数学活动中获得成功的体验,培养学生独立思考和探究问题的意识和能力。
教学准备:多媒体课件。
教学过程:
1.导入故事《朝三暮四》,引发学生思考。根据学生回答板书:
3+4=7(个)4+3=7(个)3+4=4+3
2.创设问题情景。出示主题图,引导学生观察,图中告诉了我们哪些信息?我们要解决的问题是什么?
3.尝试解决问题。学生独立解决问题,根据学生解答板书:
40+56=96(千米)56+40=96(千米)40+56=56+40
引发猜想:是否任意两数相加,交换位置,和都不变?
1.交流:有了猜想,我们还得验证。你打算怎么验证?
2.学生举例验证,教师巡视指导。
1.同学们仔细观察列举出的等式,说一说你发现了什么?你能用自己的话说出你发现的规律,并给它命名吗?(两个加数交换位置,和不变。这叫加法交换律。)
2.让学生用自己喜欢的方式表示加法交换律。用语言表达加法交换律比较麻烦,怎样表示既简单又清楚呢?试一试,用你喜欢的符号、字母或图形表示两个加数。
1.引导学生由加法类比到减法、乘法和除法,并自觉形成关于减法、乘法和除法中是否有交换律的三个新猜想。
2.学生选择部分猜想,举例进行研究。教师参与,适时给予指导。
3.交流:哪一种猜想是正确的,你们是怎么举例验证得出结论的?教师板书若干例子,进而得出结论。
4.探讨:减法和除法中有交换律吗?学生交流后,引导思考:为什么只要举一个反例就能推翻猜想?
1.请同学们想一想,以前学过的知识中哪些地方用到过加法交换律?
2.下面我们就来比一比,看谁学得最好。
(1)你能在括号里填上合适的数吗?
300+600=()+()()+55=55+420 ()+65=()+35
(2)仔细看一看,下面的算式符合加法交换律吗?
270+380=380+270 b+800=800+b
(3)运用加法交换律,你能写出几个算式?写写试试吧。
25+49+75=()+()+()
学生写出算式以后,让学生观察这些算式,哪两个数交换了位置?在这些算式中,你认为哪一道计算起来比较简单?说说你的想法。
通过这节课的学习,你有哪些收获?说一说自己表现最好的方面。
(责任编辑付淑霞)
加法交换律教学方法篇五
教学目标
1、探索和理解加法交换律,并能灵活运用。
2、感受数学与现实生活的联系,并能用所学知识解决简单的实际问题。 教学重、难点
从现实的问题情景中抽象概括出加法交换律。
教学过程
一、诱趣激学
同学们喜欢看动画片吗?老师这里有一个小动画
1·动画片《朝三暮四》
2·引发思考,感知规律
看完这个动画片,你想对同学们说些什么?(如果学生们笑了,就借机问问学生们笑什么?)引导说出:
4+3=7(个) 3+4=7(个)课件出示
问:这两个算式有什么联系?(得数都等于7,都表示猴子一天吃的桃子)。这两个算式之间可以用什么数学符号连接起来呢?(等号)
课件演示:4+3=3+4
二、自主探究,寻找规律
1.解决问题,发现规律
谈话:其实这样的数学问题就在我们身边,同学们会骑自行吗?(会),李叔叔也会骑车,他这里有一个问题需要我们帮忙解决一下。 课件出示骑车主题图。
问:从中你可以得到哪些信息?要求什么呢?(上午骑了40千米,下午骑了56千米,今天一共骑了多少千米?)
问:一共骑了多少千米?能列式计算解决这个问题吗?(能)
请在草稿本上做,老师下去找到需要的答案,板书黑板。
40+56=96(千米)56+40=96(千米)
问:观察这两个同学的列式,你们发现呢什么?
两个算式计算的结果都是一样的,我们可以用等号连接起来。
课件出示40+56=96(千米)56+40=96(千米)
40+56=56+40
2.举例猜想,概括规律
课件出示4+3=3+440+56=56+40
观察这两组算式,都是两边计算的结果相等,可以用等号连接,你能再举出几个这样的列子吗?同桌互相交流。
全班交流,把学生的汇报结果写在黑板上。
同学们真聪明,举了这么多的列子,你能发现什么规律吗?请用最简洁的话概括出来。 同桌交流。
全班交流,总结板书:两个加数交换位置,和不变。
问:你能给这个规律起个名字吗?(加法交换律)
我把加数换成其他任意的数,交换律还成立吗?老师这里有几组算式 课件出示讲解过程
① 30+20 两位数加上两位数,交换加数的位置,和是不变
② 100+30 三位数加上两位数,交换加数的位置,和也是不变
③ 1000+200 四位数加上三位数,交换加数的位置,和还是不变
刚才经过同学们的努力,我们发现了不管这两个加数是什么,只要两个加数交换了位置,他们的和不变。我们把这个规律叫做加法交换律。(板书:加法交换律)课件出示加法交换律的内容。
3.用喜欢的方式表示规律
怎样表示任意两数相加,交换加数位置和不变呢?你能用自己喜欢的方式表示吗?
请同学们相互讨论,老师下去帮助同学
全班交流 想法一:甲数+乙数=乙数+甲数
想法二:□+○=○+□
想法三:a+b=b+a
师:同学们各抒己见,用了这么多的方式表示。同学们觉得哪一种最好呢?为什么?(简洁明了。)
课件出示:a+b=b+a
谈话:咱们知道了加法交换律,并且会用自己喜欢的方式表示,请同学们想一想,以前学过的知识中,哪些地方用到过加法交换律(验算加法时)
课件演示876+1924
4.思考题,拓展规律
下面这个等式应用了加法交换律吗?
课件出示3+4+5=4+3+5
在三个数相加里面,我们也可以用加法交换律
运用加法交换律,在括号里填上适当的数
355+423=423+()
258+( ) =340+()
a+268=268+( )
35+42+65=35+()+( )
总结:这节课上,同学们个个表现都很棒,积极思考,踊跃回答问题,学习热情不断高涨,数学家们总结的规律,我们也能发现,同学们真棒,想一想我们探索加法交换律的过程,你有什么收获呢?
加法交换律教学方法篇六
教学目标
1、让学生在经历探索加法交换律和加法结合律的过程中,理解并掌握加法交换律和加法结合律,初步感受到应用加法运算律可以使一些计算简便。
2、在探索运算律的过程中,发展学生的分析、比较、抽象、概括能力 ,培养学生的符号感。
3、让学生在数学活动中获得成功的体验,进一步增强对数学学习的兴趣和信心,初步形成独立思考和探究问题的意识和习惯。
教学重点
理解加法的运算律。
教学难点
概括加法的运算律,尝试用字母表示。
教学过程
二、教学加法交律。
1、课件出示:这是同学们课外活动的情况。谁能来解决这个问题?根据学生回答,联系题意讲解,并板书:28+17=45(人),问:还可能怎样想:17+28=45(人)。
板书算式。
2、比较这两道算式有什么不同?
3、得数相同的算式我们可以用等号把它们连成等式。
4、举例:你能再说出几个这样的等式吗?自己写一写。学生说,老师相机板书等式,并追问:介绍一下你是怎么写的?核实是否相等。
5、概括规律:仔细观察,有什么规律?根据学生回答,相机引导发现规律。
6、用自己喜欢的方式表示这个规律?可适当提示:用符号、文字、字母
学生思考,充分发表自己意见,教师给予肯定。
7、数学上,我们一般用a、b表示两个加数,可以写成:a+b=b+a.老师小结:
引出:加法交换律(板书)
8、小练习:填数
1、过渡:刚才我们一起动脑,有了很多发现,大家真不简单。现在我们再来解决一个问题,看看会有哪些收获?课件出示
2、列式解答,利用题意追问算式含义,并相机加括号表示先算。还可能先算什么?说算式含义
3、比较这两个算式:有什么不同?什么相同?得数为什么相同?我们可以用等号连成等式。
4、出示书上题目,说一说,算一算。
5、概括规律:仔细观察,你有什么发现?学生回答,教师引导发现规律。
6、你能不能再举几个例子?学生举例。
7、教师小结,引出:加法结合律(板书)。如果用a、b、c分别表示这三个加数,加法结合律可以表示成?
8、小练习:填数。
1、刚才我们学习了加法交换律和加法结合律,它们都是运用在加法中的规律。师总结。
2、课后练习:
(1)下面等式各应用了什么运算律?学生说一说,对第三道重点分析,引出加法运算律有作用。
(2)比较体会运算律的作用,知道凑整百。
(3)凑整百小练习。
加法交换律教学方法篇七
������ñ§ï¿½ï¿½ï¿½ï¿½
�����ì²ï¿½p28ò³ï¿½ï¿½1��p30ò³ï¿½ï¿½ï°ï¿½ï¿½ï¿½ï°ï¿½â¡£
������ñ§ä¿ï¿½ï¿½
����1��öªê¶ï¿½ë¼¼ï¿½ü£ï¿½
������ï¾ï¿½ï¿½ï¿½ï¿½ï¿½é¾³ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ï¿½ê¶ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½éµäºï¿½ï¿½å¡£
����2�������뷽����������ä¸ê½ï¿½ó±ï¿½ê¾ï¿½ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½é£ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ó¦ï¿½ã¼ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½é½ï¿½ï¿½ï¿½ò»ð©ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ã¡£
����3�����ì¬ï¿½ï¿½ï¿½ï¿½ï¿½öµï¿½û£ï¿½
��������������ì½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ü³é¹ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ã£ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ï°ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ä£ï¿½ï¿½ï¿½õ¹ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ä»ï¿½ï¿½ï¿½ï¿½ï¿½ð¡ï¿½
����������ñ§ï¿½ï¿½ï¿½û²ì£¬ï¿½è½ï£ï¿½ï¿½ï¿½ï¿½ó£¬¸ï¿½ï¿½ï¿½ï¿½ä³ï¿½ï¿½ï¿½ë¼î¬ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½
������ñ§ï¿½øµï¿½
������ê¶ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½éµäºï¿½ï¿½å¡£
������ñ§ï¿½ñµï¿½
��������ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ó£¬¸ï¿½ï¿½ï¿½ï¿½ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½é¡ï¿½
������ñ§ï¿½ã¾ï¿½
������ã½ï¿½ï¿½î¼ï¿½ï¿½ï¿½
������ñ§ï¿½ï¿½ï¿½ï¿½
����
������ò»ï¿½ï¿½ï¿½ï¿½ê¾ï¿½ï¿½ñ§ï¿½ï¿½ï¿½
������ñ§ï¿½ï¿½ù£ï¿½ï¿½ì²ï¿½p28ò³ï¿½ï¿½1���������ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½â£¬ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½×¢ï¿½ï¿½
����1��������1�龳í¼ï¿½ï¿½ï¿½ï¿½ï¢ï¿½ð³ï¿½ï¿½ï¿½ê½ï¿½ï¿½
����2������ï²ï¿½ï¿½ï¿½ä·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ô¼ï¿½ï¿½ï¿½
����3��í¬ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ô¼ï¿½ï¿½ï¿½ï¿½ã·¨
����4����ê¦ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ê½ï¿½ï¿½ï¿½ï¿½
����40+56=96��ç§ï¿½×£ï¿½ 56+40=96��ç§ï¿½×£ï¿½
����5���ô±ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ê½ï¿½ï¿½ï¿½ã·¢ï¿½ï¿½ï¿½ï¿½ê²ã´ï¿½ï¿½ï¿½ï¿½ï¿½ô¼ï¿½ï¿½ä»ï¿½ëµò»ëµï¿½ï¿½
����������ñ§ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ù£ï¿½ï¿½ï¿½ñ§ï¿½ì²ï¿½p28ò³ï¿½ï¿½1���������ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½â£¬ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½×¢ï¿½ï¿½
������ñ§ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ï¿½ê¦ï¿½ú²ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ï¿½ç°ï¿½ï¿½ï¿½ï¿½ñ²ï¿½ï¿½ö¸ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ö¹ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½â£¬ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ñ§ï¿½é£©
������������ñ§ï¿½ï¿½ï¿½
����1�����
����387+425=�� ��+ 387 525+�� ��=137+ 525
����300+600=�� ��+�� �� �� ��+65=�� ��+35
��������+����=�� ��+�� �� å¼ï¿½ï¿½+�� ��=����+�� ��
����2������
����56+68 50+b
����b+50 68+56
����
������ò»ï¿½ï¿½ð¡ï¿½é»¥ì½ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½â£¬í¬ï¿½ï¿½ï¿½ï¿½ñ§ï°ð¡ï¿½ï¿½ï¿½ú»ï¿½ï¿½à½»ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ð¡ï¿½ï¿½ò²ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ëµï¿½ï¿½ï¿½ï¿½ï¿½çºã£ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ê±ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ï°ð¡ï¿½ï¿½ï¿½ï¿½ê¦ï¿½ï¿½ï¿½â¡£ï¿½ï¿½
����������ñ§ï¿½ï¿½ï¿½ï¿½è·ï¿½ø¼ï¿½ï¿½ã£¬ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ö¹ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ì½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ê¦ñ²ï¿½ø¸ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ö¡ï¿½ï¿½õ¼ï¿½ñ§ï¿½ï¿½ï¿½ï¿½ï¿½úµï¿½ï¿½ï¿½ï¿½â£©
����������ê¦ï¿½ï¿½ï¿½ï¿½ì½
����1������ð¡ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½â¡£
������1����ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½â£¬ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½
������2����ê¦ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½â¡£
������3���������ä¸ï¿½ï¿½ê¾ï¿½ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½éºí½ï¿½ï¿½ï¿½é£ï¿½
������4������ä¸ï¿½ï¿½ê¾ï¿½ï¿½ð©ï¿½ï¿½ï¿½ã¶¨ï¿½ï¿½ï¿½ï¿½ê²ã´ï¿½åµã£¿
����2����ê¦ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ôµï¿½ï¿½ë²»í¬ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½í¬ñ§ï¿½ã±¨ï¿½ô¼ï¿½ï¿½ä½ï¿½ï¿½ï¿½ë¼â·ï¿½ë·½ï¿½ï¿½ï¿½ï¿½
����
����1������⡣
������1��360+482=�� ��+ 360 128+275=125+�� ��
������2���� ��+ 78 =78 +149 133+�� ��=125+133
����2�����ߡ�
����38+175 47+b
����b+47 175+38
����3��������������⡣
����89+91+11 268+147+32
��������ð¡ï¿½á£ºì¸ì¸ï¿½ï¿½ï¿½ï¿½ê²ã´ï¿½õ»ï¿½ï¿½ï¿½ê²ã´ï¿½ï¿½ï¿½ü£ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ð£¿£ï¿½ñ§ï¿½ï¿½ï¿½ü½á²»ï¿½ï¿½ï¿½ï¿½ï¿½äµø·ï¿½ï¿½ï¿½ï¿½ï¿½ê¦òªï¿½êµï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ü½á£©
����
������ò»ï¿½ï¿½ï¿½ï¿½ê¾ï¿½ï¿½ï¿½ï¿½â£¨1��2�������3��ñ¡ï¿½ï¿½ï¿½ï¿½4��ë¼ï¿½ï¿½ï¿½â£©
����1�����ý¼ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½õ¡ï¿½
������1��450+320=�� ��+ 450 65+95=95+�� ��
������2���� ��+ 100 =100+150 250+�� ��=125+�� ��
����2���������ð©ï¿½ï¿½ê½ï¿½ï¿½ï¿½ï¼ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½é¡ï¿½
������1��84 + c = b + 84
������2��10 + 20 + 30 + 40 =10 + (20 + 30) + 40
����3�������㡣
����81+78+19 679+132+121
�������������巴����
������òµï¿½ï¿½ï¿½ï¿½
�����ì²ï¿½p30ò³ï°ï¿½â¡£
�����������
�����ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½
����40+56=96��ç§ï¿½×£ï¿½ 56+40 =96��ç§ï¿½×£ï¿½
����a+b = b+a
加法交换律教学方法篇八
�������������î¾ï¿½ï¿½ï¿½ï¿½ð¡ñ§ï¿½ï¿½ñ§ï°ï¿½ï¿½ñ§ï¿½ä±ï¿½ï¿½ï¿½æ¸ï¿½ï¿½ï¿½ò²ï¿½ï¿½ï¿½ï¿½ï¿½ç½ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ì½ï¿½ï¿½ï¿½ä»ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ê¦ó¦ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ðµï¿½ï¿½ï¿½ï¿½î¾ï¿½é£¬ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ú´ë»ï¿½ï¿½ï¿½ï¿½ï¿½êµï¿½ö¶ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ù´ï¿½ï¿½ì£¬ï¿½ï¿½êµï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ïµï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ñ§öªê¶ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½õ¹ï¿½ï¿½ï¿½î³éµä¹ï¿½ï¿½ì£ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ó¦ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½êµï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½
�����ì²ä·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ì²ä´ï¿½ï¿½é¾³ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½â£¬ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ã¶¨ï¿½éµï¿½ï¿½ï¿½êµï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½êµï¿½ï¿½ï¿½ï¿½ï¿½â£¬ï¿½ï¿½ò»ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ê¶ï¿½ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½é£ï¿½ê¹ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½é¸ï¿½ï¿½ï¿½ò»ï¿½ã£¬ï¿½é¾ï¿½ï¿½åµ½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½öªï¿½ï¿½ï¿½ì£ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½é¸ï¿½ï¿½ï¿½ï¿½ï¿½ê¶ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ò»ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ê¶ï¿½ï¿½
������ñ§ä¿ï¿½ê£ºì½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½é£ï¿½ï¿½ï¿½ï¿½ü¹ï¿½ï¿½ï¿½ï¿½ï¿½ä¸ï¿½ï¿½ï¿½ï¿½ê¾ï¿½ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½é£ï¿½ï¿½ï¿½ï¿½ï¿½ì½ï¿½ï¿½ï¿½ï¿½ï¿½ã¶¨ï¿½é¹ï¿½ï¿½ì£ï¿½í¨ï¿½ï¿½ï¿½ï¿½êµï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ä½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ð±è½ïºí·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ö²ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½é£ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ï¿½î¶¯ï¿½ð»ï¿½ã³é¹ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½é£¬ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ë¼ï¿½ï¿½ï¿½ï¿½ì½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ê¶ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½
������ñ§×¼ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ã½ï¿½ï¿½î¼ï¿½ï¿½ï¿½
������ñ§ï¿½ï¿½ï¿½ì£ï¿½
����
����1.������â¡ï¿½ï¿½ï¿½ï¿½ï¿½äºï¿½ä¡ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ë¼ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ø´ï¿½ï¿½ï¿½é£º
����3��4��7������4��3��7������3��4��4��3
����2.���������龰����ê¾ï¿½ï¿½ï¿½ï¿½í¼ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½û²ì£¬í¼ï¿½ð¸ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ð©ï¿½ï¿½ï¢ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½òªï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ê²ã´ï¿½ï¿½
����3.���ô½ï¿½ï¿½ï¿½ï¿½ï¿½â¡£ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½â£¬ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½é£º
����40��56��96��ç§ï¿½×£ï¿½56��40��96��ç§ï¿½×£ï¿½40��56��56��40
�����������룺�ç·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ó£ï¿½ï¿½ï¿½ï¿½ï¿½î»ï¿½ã£ï¿½ï¿½í¶ï¿½ï¿½ï¿½ï¿½ä£¿
����
����1.���������ë²ï¿½ï¿½ë£¬ï¿½ï¿½ï¿½ç»ï¿½ï¿½ï¿½ï¿½ï¿½ö¤ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ã´ï¿½ï¿½ö¤ï¿½ï¿½
����2.ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ö¤ï¿½ï¿½ï¿½ï¿½ê¦ñ²ï¿½ï¿½ö¸ï¿½ï¿½ï¿½ï¿½
����
����1.í¬ñ§ï¿½ï¿½ï¿½ï¿½ï¸ï¿½û²ï¿½ï¿½ð¾ù³ï¿½ï¿½äµï¿½ê½ï¿½ï¿½ëµò»ëµï¿½ã·¢ï¿½ï¿½ï¿½ï¿½ê²ã´ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ô¼ï¿½ï¿½ä»ï¿½ëµï¿½ï¿½ï¿½ã·¢ï¿½öµä¹ï¿½ï¿½é£ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ð£¿£ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½î»ï¿½ã£ï¿½ï¿½í²ï¿½ï¿½ä¡£ï¿½ï¿½ð¼ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½é¡ï¿½ï¿½ï¿½
����2.��ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ô¼ï¿½ï²ï¿½ï¿½ï¿½ä·ï¿½ê½ï¿½ï¿½ê¾ï¿½ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½é¡ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ô±ï¿½ï¿½ï¿½ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½é±è½ï¿½ï¿½é·³ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ê¾ï¿½è¼ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ø£ï¿½ï¿½ï¿½ò»ï¿½ô£ï¿½ï¿½ï¿½ï¿½ï¿½ï²ï¿½ï¿½ï¿½ä·ï¿½ï¿½å¡ï¿½ï¿½ï¿½ä¸ï¿½ï¿½í¼ï¿½î±ï¿½ê¾ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½
����
����1.����ñ§ï¿½ï¿½ï¿½é¼ó·ï¿½ï¿½ï¿½èµï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ë·ï¿½ï¿½í³ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ô¾ï¿½ï¿½î³é¹ï¿½ï¿½ú¼ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ë·ï¿½ï¿½í³ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ç·ï¿½ï¿½ð½ï¿½ï¿½ï¿½ï¿½éµï¿½ï¿½ï¿½ï¿½ï¿½ï¿½â²ï¿½ï¿½ë¡£
����2.ñ§ï¿½ï¿½ñ¡ï¿½ñ²¿·ö²ï¿½ï¿½ë£¬ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ð¾ï¿½ï¿½ï¿½ï¿½ï¿½ê¦ï¿½ï¿½ï¿½ë£¬ï¿½ï¿½ê±ï¿½ï¿½ï¿½ï¿½ö¸ï¿½ï¿½ï¿½ï¿½
����3.��������ò»ï¿½ö²ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½è·ï¿½ä£ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ã´ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ö¤ï¿½ã³ï¿½ï¿½ï¿½ï¿½ûµä£ï¿½ï¿½ï¿½ê¦ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ó£ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ã³ï¿½ï¿½ï¿½ï¿½û¡ï¿½
����4.ì½ï¿½ö£ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½í³ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ð½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ë¼ï¿½ï¿½ï¿½ï¿½îªê²ã´ö»òªï¿½ï¿½ò»ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½æ·ï¿½ï¿½ï¿½ï¿½ë£¿
����
����1.��í¬ñ§ï¿½ï¿½ï¿½ï¿½ò»ï¿½ë£¬ï¿½ï¿½ç°ñ§ï¿½ï¿½ï¿½ï¿½öªê¶ï¿½ï¿½ï¿½ï¿½ð©ï¿½ø·ï¿½ï¿½ãµï¿½ï¿½ï¿½ï¿½ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½é£ï¿½
����2.�������ç¾ï¿½ï¿½ï¿½ï¿½ï¿½ò»ï¿½è£ï¿½ï¿½ï¿½ëñ§ï¿½ï¿½ï¿½ï¿½ã¡ï¿½
������1�����������������ïºï¿½ï¿½êµï¿½ï¿½ï¿½ï¿½ï¿½
����300+600=����+��������+55=55+420 ����+65=����+35
������2����ï¸ï¿½ï¿½ò»ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ê½ï¿½ï¿½ï¿½ï¼ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½
����270+380=380+270 b+800=800+b
������3�����ã¼ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½é£ï¿½ï¿½ï¿½ï¿½ï¿½ð´ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ê½ï¿½ï¿½ð´ð´ï¿½ï¿½ï¿½ô°é¡ï¿½
����25+49+75=����+����+����
����ñ§ï¿½ï¿½ð´ï¿½ï¿½ï¿½ï¿½ê½ï¿½ôºï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½û²ï¿½ï¿½ï¿½ð©ï¿½ï¿½ê½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½î»ï¿½ã£ï¿½ï¿½ï¿½ï¿½ï¿½ð©ï¿½ï¿½ê½ï¿½ð£ï¿½ï¿½ï¿½ï¿½ï¿½îªï¿½ï¿½ò»ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½è½ï¼òµ¥£ï¿½ëµëµï¿½ï¿½ï¿½ï¿½ë·¨ï¿½ï¿½
����
����í¨ï¿½ï¿½ï¿½ï¿½ú¿îµï¿½ñ§ï°ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ð©ï¿½õ»ï¿½ëµò»ëµï¿½ô¼ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ãµä·ï¿½ï¿½æ¡£
���������î±à¼ï¿½ï¿½ï¿½ï¿½ï¼ï¿½ï¿½
加法交换律教学方法篇九
����
����1��öªê¶ï¿½ë¼¼ï¿½ü£ï¿½ï¿½ù½ï¿½ï¾ï¿½ï¿½ï¿½ï¿½ï¿½é¾³ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ï¿½ê¶ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½éµäºï¿½ï¿½å¡£
����2�������뷽����������ä¸ê½ï¿½ó±ï¿½ê¾ï¿½ó·ï¿½ï¿½ï¿½ï¿½ï¿½é£ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ó¦ï¿½ã¼ó·ï¿½ï¿½ï¿½ï¿½ï¿½é½ï¿½ï¿½ï¿½ò»ð©ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ã¡£
����3�����ì¬ï¿½ï¿½ï¿½ï¿½ï¿½öµï¿½û£ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ì½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ü³é¹ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ã£ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ï°ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ä£ï¿½ï¿½ï¿½õ¹ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ä»ï¿½ï¿½ï¿½ï¿½ï¿½ð¡ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½û²ì£¬ï¿½è½ï£ï¿½ï¿½ï¿½ï¿½ó£¬¸ï¿½ï¿½ï¿½ï¿½ä³ï¿½ï¿½ï¿½ë¼î¬ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½
����
������ê¶ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ó·ï¿½ï¿½ï¿½ï¿½ï¿½éµäºï¿½ï¿½å¡£
����
��������ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ó£¬¸ï¿½ï¿½ï¿½ï¿½ó·ï¿½ï¿½ï¿½ï¿½ï¿½é¡ï¿½
����
������ã½ï¿½ï¿½î¼ï¿½ï¿½ï¿½
����
����ò»ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ï°
������ò»ï¿½ï¿½ï¿½ï¿½ê¾ï¿½ï¿½ñ§ï¿½ï¿½ï¿½
������ñ§ï¿½ï¿½ù£ï¿½p29ò³ï¿½ï¿½2�������ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½â£¬ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½×¢ï¿½ï¿½
����1��������2�龳í¼ï¿½ï¿½ï¿½ï¿½ï¢ï¿½ð³ï¿½ï¿½ï¿½ê½ï¿½ï¿½
����2������ï²ï¿½ï¿½ï¿½ä·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ô¼ï¿½ï¿½ï¿½
����3��í¬ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ô¼ï¿½ï¿½ï¿½ï¿½ã·¨
����4����ê¦ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ê½ï¿½ï¿½ï¿½ï¿½
����88+104+96 88+��104+96��
����=192+96 =88+200
����=288 =288
����5���ô±ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ê½ï¿½ï¿½ï¿½ã·¢ï¿½ï¿½ï¿½ï¿½ê²ã´ï¿½ï¿½ï¿½ï¿½ï¿½ô¼ï¿½ï¿½ä»ï¿½ëµò»ëµï¿½ï¿½
����������ñ§ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ù£ï¿½ï¿½ï¿½ñ§ï¿½ì²ï¿½p29ò³ï¿½ï¿½2���������ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½â£¬ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½×¢ï¿½ï¿½
������ñ§ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ï¿½ê¦ï¿½ú²ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ï¿½ç°ï¿½ï¿½ï¿½ï¿½ñ²ï¿½ï¿½ö¸ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ö¹ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½â£¬ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ñ§ï¿½é£©
������������ñ§ï¿½ï¿½ï¿½
����1�����
����387+425=�� ��+ 387 525+�� ��=137+ 525
����300+600=�� ��+�� �� �� ��+65=�� ��+35
����2������
����56+68 150+��25+75��
����150+25+75 50+b
����b+50 68+56
����a+b+100 a+(b+100 )
������������ì½ï¿½ï¿½
������ò»ï¿½ï¿½ð¡ï¿½é»¥ì½ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½â£¬í¬ï¿½ï¿½ï¿½ï¿½ñ§ï°ð¡ï¿½ï¿½ï¿½ú»ï¿½ï¿½à½»ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ð¡ï¿½ï¿½ò²ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ëµï¿½ï¿½ï¿½ï¿½ï¿½çºã£ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ê±ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ï°ð¡ï¿½ï¿½ï¿½ï¿½ê¦ï¿½ï¿½ï¿½â¡£ï¿½ï¿½
����������ñ§ï¿½ï¿½ï¿½ï¿½è·ï¿½ø¼ï¿½ï¿½ã£¬ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ö¹ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ì½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ê¦ñ²ï¿½ø¸ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ö¡ï¿½ï¿½õ¼ï¿½ñ§ï¿½ï¿½ï¿½ï¿½ï¿½úµï¿½ï¿½ï¿½ï¿½â£©
����������ê¦ï¿½ï¿½ï¿½ï¿½ì½
����1������ð¡ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½â¡£
������1����ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½â£¬ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½
������2����ê¦ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½â¡£
������3���������ä¸ï¿½ï¿½ê¾ï¿½ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½éºí½ï¿½ï¿½ï¿½é£ï¿½
������4������ä¸ï¿½ï¿½ê¾ï¿½ï¿½ð©ï¿½ï¿½ï¿½ã¶¨ï¿½ï¿½ï¿½ï¿½ê²ã´ï¿½åµã£¿
����2����ê¦ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ôµï¿½ï¿½ë²»í¬ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½í¬ñ§ï¿½ã±¨ï¿½ô¼ï¿½ï¿½ä½ï¿½ï¿½ï¿½ë¼â·ï¿½ë·½ï¿½ï¿½ï¿½ï¿½
�����ä¡ï¿½ï¿½ï¿½ï¿½ñµï¿½ï¿½ï¿½ï¿½1--3�������4��ñ¡ï¿½ï¿½ï¿½ï¿½5��ë¼ï¿½ï¿½ï¿½â£©
����1�����ý¼ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½â¡£
������1��78+25+22 =78 +�� ��+25
������2��376+175+25=376 +�� + ��
����2�����ߡ�
����147+��72+28�� a+(b+100 ��
����a+b+100 147+72+28
����3��������������⡣
����52+27+73 285+15+77+23
��������ð¡ï¿½á£ºì¸ì¸ï¿½ï¿½ï¿½ï¿½ê²ã´ï¿½õ»ï¿½ï¿½ï¿½ê²ã´ï¿½ï¿½ï¿½ü£ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ð£¿£ï¿½ñ§ï¿½ï¿½ï¿½ü½á²»ï¿½ï¿½ï¿½ï¿½ï¿½äµø·ï¿½ï¿½ï¿½ï¿½ï¿½ê¦òªï¿½êµï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ü½á£©
�����塢������
������ò»ï¿½ï¿½ï¿½ï¿½ê¾ï¿½ï¿½ï¿½ï¿½ï¿½
����1����駼ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ã¶¨ï¿½ï¿½ï¿½ï¿½ï¿½
������1��450+320=�� ��+ 450 65+95=95+�� ��
������2���� ��+ 100 =100+150 250+�� ��=125+250
������3��78+25+22 =��78 + ��+�� ��
������4��495+125+75=495 +�� + ��
����2���������ð©ï¿½ï¿½ê½ï¿½ï¿½ï¿½ï¼ó·ï¿½ï¿½ï¿½ï¿½ï¿½é£ï¿½ï¿½ï¿½ð©ï¿½ï¿½ê½ï¿½ï¿½ï¿½ï¼ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½é¡ï¿½
������1��a + �� 30+9 ��=a+ 30+9
������2��15+ ( 7+b )= (15 + 7 )+b
������3��10 + 20 + 30 + 40 =10 + (20 + 30) + 40
����3�����ߡ�
����87+22+78 ��79+83)+17
����498+125+75 498+(125+75)
����(138+136��+162 87+��22+78 ��
����79+��83+17�� 138+136+162
����4�������㡣
����98+72+28 215+85+73+27
�������������巴����
������òµï¿½ï¿½ï¿½ï¿½
加法交换律教学方法篇十
����
�����ൺ��ð¡ñ§ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ê¼¶ï¿½â²ï¿½ï¿½ò»ï¿½ï¿½ôªï¿½ï¿½ï¢ï¿½ï¿½ï¿½ï¿½13ò³ï¿½ï¿½14ò³ï¿½ï¿½`���ý¡ï¿½
����
����1����ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ì½ï¿½ï¿½ï¿½ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½éµä¹ï¿½ï¿½ì£ï¿½ï¿½ï¿½ï¿½â²¢ï¿½ï¿½ï¿½õ¼ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½éºí½ï¿½ï¿½ï¿½é£ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ä¸ï¿½ï¿½ï¿½ï¿½ê¾ï¿½ï¿½
����2����ì½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½éµä¹ï¿½ï¿½ï¿½ï¿½ð£ï¿½ï¿½ï¿½õ¹ñ§ï¿½ï¿½ï¿½ä¹û²ì¡¢ï¿½è½ï¡ï¿½ï¿½ï¿½ï¿½ó¡¢¸ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ä·ï¿½ï¿½å¸ð¡ï¿½
����3.��ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ñ§ï°ï¿½ï¿½ï¿½ï¿½ï¿½ð»ï¿½ï¿½ì½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½è¤ï¿½ï¿½ï¿½é¹ï¿½ï¿½ï¿½ï²ï¿½ã£ï¿½ï¿½ï¿½ò»ï¿½ï¿½ï¿½ï¿½ç¿ï¿½ï¿½ï¿½ï¿½ñ§ñ§ï°ï¿½ï¿½ï¿½ï¿½è¤ï¿½ï¿½ï¿½ï¿½ï¿½ä¡ï¿½
����4.�����î³é¶ï¿½ï¿½ï¿½ë¼ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ê¶ï¿½ï¿½ï°ï¿½ß¡ï¿½
����
�����������õ¼ó·ï¿½ï¿½ä½ï¿½ï¿½ï¿½ï¿½éºí½ï¿½ï¿½ï¿½é£ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ä¸ï¿½ï¿½ê¾ï¿½ï¿½ï¿½ç¡ï¿½
����
��������ñ§ï¿½ï¿½í¨ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½,����ó¶ï¿½ï¿½ô¼ï¿½ï¿½ï¿½ï¿½ö²ï¿½ï¿½ü½ï¿½ï¿½ï¿½ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½é¡ï¿½ï¿½ó·ï¿½ï¿½ï¿½ï¿½ï¿½éµä¹ï¿½ï¿½ì¡ï¿½
����
�����î¼ï¿½ï¿½ï¿½í¶ó°ï¿½ç¡ï¿½ï¿½ï¿½æ¬
����
����ò»ï¿½ï¿½ï¿½â¶¨ï¿½ï¿½ñ§ï¿½ï¿½ù£ï¿½ï¿½ï¿½ï¿½ï¿½ô¤ï°
������ò»ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½é¾³
����1��ì¸ï¿½ï¿½ï¿½ï¿½í¬ñ§ï¿½ç£ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½æºó¾ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ð¹ï¿½ï¿½ï¿½ø£ï¿½ï¿½ø±ï¿½ï¿½ç»æºó±ï¿½ï¿½ï¿½îªï¿½ï¿½ï¿½çµä¡ï¿½ä¸ï¿½×ºó¡ï¿½ï¿½ï¿½ï¿½â¼¸ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ò»ö±ï¿½ï¿½ñ§ï°ï¿½ð¹ø»æºóµï¿½öªê¶ï¿½ï¿½ï¿½ë½âµ½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ð¹ø»æºóµï¿½ï¿½ï¿½ï¢ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ä£ï¿½ï¿½ã»¹ï¿½ë½âµ½ï¿½ï¿½ð©ï¿½ð¹ø»æºóµï¿½öªê¶ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ý¿ï¿½ç°ï¿½ï¿½ï¿½ï¿½ø´ï¿½ï¿½ë²»ï¿½ï¿½ï¿½ù¶ï¿½ï¿½ë½ï¿½ò»ð©ï¿½ï¿½
�����î¼ï¿½õ¹ê¾ï¿½é¾³â¼ï¿½ñ£º£ï¿½ï¿½î¼ï¿½õ¹ê¾ï¿½ä¹ø¼ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½öªï¿½ï¿½ï¿½æºï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ð¡öªê¶,�������î£ï¿½ï¿½ï¿½ø¸ï¿½ô������ô���é¹å¸ï¿½ô���î£ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ô���î£ï¿½ï¿½ï¿½ï¿½ï¿½æ½ô��ð¡öªê¶ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ä»ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¢ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½é¾³í¼ï¿½ï¿½
��������õ¹ê¾ï¿½ú´ï¿½ï¿½ï¿½ï¿½ç°ï¿½ä¾ï¿½ï¿½ç»æºï¿½ï¿½ï¿½ï¿½ï¿½í¼ï¿½ï¿½ï¿½ï¿½ê¦ï¿½ï¿½ï¿½é£ºï¿½æºï¿½ï¿½ï¿½ï¿½ï¿½
������í¬ñ§ï¿½ï¿½ï¿½ï¿½ï¸ï¿½û²ì£¬ï¿½ï¿½ï¿½ü»ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ð©ï¿½ï¿½ñ§ï¿½ï¿½ï¢ï¿½ï¿½
����ñ§ï¿½ï¿½ï¿½û²ï¿½ã±¨ï¿½ï¿½
�������㱨�����ý»æºï¿½ï¿½ï¿½ï¿½ï¿½í¼ï¿½ï¿½ï¿½ë½âµ½ï¿½æºó·ï¿½îªï¿½ï¿½ï¿½î¡ï¿½ï¿½ï¿½ï¿½îºï¿½ï¿½ï¿½ï¿½î£ï¿½1���æºï¿½ï¿½ï¿½ï¿½î³ï¿½3472ç§ï¿½×£ï¿½ï¿½ï¿½ï¿½î³ï¿½1206ç§ï¿½×£ï¿½ï¿½ï¿½ï¿½î³ï¿½786ç§ï¿½×£ï¿½2���æºï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½39��æ½ï¿½ï¿½ç§ï¿½×£ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½34��æ½ï¿½ï¿½ç§ï¿½×£ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½2��æ½ï¿½ï¿½ç§ï¿½×£ï¿½ï¿½ï¿½
������ê¦ï¿½ï¿½ê±ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ó¦ï¿½ï¿½ï¿½ï¿½ï¢ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½
����2�����ü¸ï¿½ï¿½ï¿½ï¿½ï¿½ð©ï¿½ï¿½ï¢ï¿½ï¿½ï¿½ï¿½ï¿½ð©ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ø£ï¿½ñ§ï¿½ï¿½ï¿½ú´ð¡£½ï¿½ê¦ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½â¡£
�������⣨1���æºï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ç¶ï¿½ï¿½ï¿½ï¿½ï¿½æ½ï¿½ï¿½ç§ï¿½×£ï¿½
�������⣨2���æºï¿½è«ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ç§ï¿½×£ï¿½
������������ê¾ñ§ï°ä¿ï¿½ï¿½
����í¬ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ã´ï¿½ï¿½ï¿½ð¼ï¿½öµï¿½ï¿½ï¿½ï¿½ï¿½â£¬ï¿½ï¿½ã´ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ç½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ð©ï¿½ï¿½ï¿½ï¿½ï¿½ø£ï¿½ï¿½ë¿´ï¿½ï¿½ï¿½ú¿îµï¿½ñ§ï°ä¿ï¿½ê£º
����1����ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ì½ï¿½ï¿½ï¿½ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½éµä¹ï¿½ï¿½ì£ï¿½ï¿½ï¿½ï¿½â²¢ï¿½ï¿½ï¿½õ¼ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½éºí½ï¿½ï¿½ï¿½é£ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ä¸ï¿½ï¿½ï¿½ï¿½ê¾ï¿½ï¿½ï¿½ü¹ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ã¶¨ï¿½é½ï¿½ï¿½ð¼ï¿½ï¿½ã¡£
����2����ì½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½éµä¹ï¿½ï¿½ï¿½ï¿½ð£ï¿½ï¿½ï¿½õ¹ñ§ï¿½ï¿½ï¿½ä¹û²ì¡¢ï¿½è½ï¡ï¿½ï¿½ï¿½ï¿½ó¡¢¸ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ä·ï¿½ï¿½å¸ð¡ï¿½
������������ê¾ï¿½ï¿½ñ§ö¸ï¿½ï¿½
����îªï¿½ï¿½ï¿½ü¹ï¿½ï¿½ï¿½ï¿½ãµø½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ï°ä¿ï¿½ê£¬ï¿½ï¿½ê¦ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½á¹©ï¿½ï¿½ò»ð©ö¸ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ë¿´ï¿½ï¿½ñ§ö¸ï¿½ï¿½ï¿½ï¿½
��������ñ§ö¸ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½í¬ñ§ï¿½ï¿½ï¿½ï¿½ï¿½æ¿´ï¿½ì¿ï¿½ï¿½ï¿½ï¿½13��14ò³ï¿½ï¿½ï¿½ï¿½ï¢ï¿½ï¿½3�äµï¿½ò»ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ð¡ï¿½ï¿½ï¿½ôµï¿½ï¿½ï¿½ï¿½ý£ï¿½ï¿½øµã¿´ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ä¹ï¿½ï¿½ì£ï¿½ë¼ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½1���������í¬ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½â£¿ï¿½ï¿½ï¿½ö·ï¿½ï¿½ï¿½ï¿½òµ¥£ï¿½ï¿½ï¿½2��ê²ã´ï¿½ç¼ó·ï¿½ï¿½ä½ï¿½ï¿½ï¿½é£ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ä¸ê½ï¿½ï¿½ê¾ï¿½ï¿½ï¿½ï¿½3��ê²ã´ï¿½ç¼ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½é£ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ä¸ê½ï¿½ï¿½ê¾ï¿½ï¿½
������5���óºó£¬±ï¿½ò»ï¿½ï¿½ë�㱨�����������
�������ä£ï¿½ñ§ï¿½ï¿½ï¿½ï¿½ñ§
����ê¦ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½í¬ñ§ï¿½ç¸ï¿½ï¿½ý¡ï¿½ï¿½ï¿½ñ§ö¸ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ê¼ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ï¿½ò»ï¿½ï¿½ë���������棬ë��ñ§ð§ï¿½ï¿½ï¿½ï¿½ã£ï¿½ï¿½ï¿½ê¦ä¿ï¿½ï¿½ñ²ï¿½ï¿½ã¿ò»ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ø±ï¿½òªï¿½ï¿½×¢ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½
���������㱨��������������
������ò»ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½
����ê¦ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½í¬ñ§ï¿½ï¿½ï¿½ï¿½ö£ï¿½
����������è«ï¿½ï¿½ã±¨
����1������ò»ï¿½ï¿½ï¿½æºï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ç¶ï¿½ï¿½ï¿½ï¿½ï¿½æ½ï¿½ï¿½ç§ï¿½×£ï¿½
����ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ê½ï¿½ï¿½ï¿½ê±ï¿½ï¿½ï¿½ï¿½ï¿½ü»ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½
������1��39��34��2��34��2��39
������2����39��34����2��39����34��2����
����2����������æºï¿½è«ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ç§ï¿½×£ï¿½
����ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ü³ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½
������1����3470+1210+790��1210+790+3470
������2����3470+1210��+790��3470+��1210+790����
������������òªñ§ï¿½ï¿½öªê¶ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ê½ï¿½ð¡ï¿½
�����������í¼ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ã½ì²ï¿½ï¿½é¾³í¼ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ï¿½è¡ï¿½ï¿½ï¢ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ó·ï¿½ï¿½ï¿½ï¿½â¡£ï¿½ú´ë»ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ð³ï¿½ï¿½ï¿½ê½ï¿½ï¿½í¨ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ê½ñ§ï°ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½öªê¶ï¿½ï¿½îªï¿½ï¿½ï¿½ï¿½ñ§ï°ï¿½ï¿½ï¿½ï¿½ï¿½ë·ï¿½ï¿½ê¡ï¿½ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï°ñ¾ï¿½ï¿½ï¿½í¶ï¿½ëµ½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ê½ï¿½ï¿½ï¿½ð¾ï¿½ï¿½ð£ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ì½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½è¤ï¿½ï¿½ï¿½ï¿½
����3���û²ì¡¢ï¿½è½ï¡ï¿½ï¿½ï¿½ï¿½ö¹ï¿½ï¿½ï¿½
������1���û²ï¿½ï¿½ï¿½ð©ï¿½ï¿½ê½ï¿½ï¿½ï¿½ï¿½ï¿½ç·ï¿½ï¿½ï¿½ï¿½ï¿½ê²ã´ï¿½ï¿½
�������㱨��ã¿ï¿½ï¿½ï¿½ï¿½ê½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½í¬ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ä½ï¿½ï¿½ï¿½ï¿½í¬ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ë³ï¿½ï¿½í¬ï¿½ï¿½
�������磺
������39��34����2��39����34��2��
������3470+1210��+790��3470+��1210+790����
������2���ç²ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ðµï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ó¶ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ð©ï¿½ï¿½ï¿½ï¿½ï¿½ø£ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ö¤ò»ï¿½â°é£ï¿½ï¿½ï¿½ã¿ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï°ï¿½ï¿½ï¿½ï¿½ð´ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ê½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½
�������㱨��
������35+63��+15=35+��63+15��
������325+82��+18=325+��82+18����
������3������ä·ï¿½ï¿½ö¸ï¿½ï¿½ß´ï¿½ò£ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ä¾ï¿½ï¿½ï¿½ï¿½ï¿½êµï¿½ï¿½í¶ó°õ¹ê¾ï¿½ï¿½
���������������ê±ï¿½ï¿½ï¿½è°ï¿½ç°ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ó£ï¿½ï¿½ï¿½ï¿½è°ñºï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ó£ï¿½ï¿½í²ï¿½ï¿½ä¡£ï¿½ï¿½
����ê¦ö¸ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½é½ï¿½ï¿½ï¿½ï¿½ó·ï¿½ï¿½ï¿½ï¿½ï¿½é¡ï¿½
������4����������ï²ï¿½ï¿½ï¿½ä·ï¿½ï¿½ï¿½ï¿½ï¿½ê¾ï¿½ï¿½ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½
����ñ§ï¿½ï¿½ï¿½ã¸ï¿½ï¿½ö·ï¿½ï¿½å¡ï¿½ï¿½ï¿½ä¸ï¿½ï¿½ê¾ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ã¶¨ï¿½é¡ï¿½ï¿½ï¿½ï¿½õ½ï¿½ê¦ö¸ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï£ï¿½ï¿½ï¿½ï¿½ï¿½í³ò»ï¿½ï¿½a��b��c����ê¾ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ë¼ó·ï¿½ï¿½ï¿½ï¿½ï¿½é¿ï¿½ï¿½ï¿½ð´ï¿½ï¿½ï¿½ï¿½a+b��+c=a+��b+c����ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ê¦ï¿½ï¿½ï¿½ï¿½ï¿½úºú°ï¿½ï¿½ï¿½
����ð¡ï¿½á£ºï¿½õ²ï¿½ï¿½ï¿½ï¿½ï¿½í¨ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½â·¢ï¿½ö²ï¿½ï¿½ï¿½ï¿½é³ï¿½ï¿½ë¼ó·ï¿½ï¿½ï¿½ï¿½ï¿½é¡ï¿½
�����������í¼ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ú¾ï¿½ï¿½ï¿½ï¿½ë²â²â¡ªï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ö¤ï¿½ï¿½ï¿½ã³ï¿½ï¿½ï¿½ï¿½ûµä¹ï¿½ï¿½ì£ï¿½ï¿½ï¿½ï¿½ï¿½ö®ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ò»ï¿½ï¿½ï¿½ï¿½ñ§ë¼ï¿½ë¡£ï¿½ï¿½
����4��ñ§ï¿½ï¿½ç¨ï¿½æ£ï¿½ì½ï¿½ï¿½ï¿½ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½é¡ï¿½
������ã´ï¿½ï¿½ï¿½ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ð»ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ä¹ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ë²»ï¿½ï¿½öªï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï·ï¿½é¡ï¿½
����(1)��ï·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ñ¡ï¿½
������ã¿ï¿½ï¿½ð¡ï¿½ï¿½ï¿½ð¶ï¿½ï¿½ï¿½ò»ï¿½ï¿½ï¿½ï¿½ê½ï¿½ï¿½æ¬ï¿½ï¿½ï¿½ï¿½í¬ñ§ï¿½ï¿½ð¡ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¸ï¿½ï¿½ò»ï¿½ë£¬ï¿½ï¿½ò»ï¿½ã£¬ï¿½ï¿½ó¦ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ä»ï¿½ï¿½ï¿½ä¸ï¿½ï¿½ï¿½ê½ï¿½äºï¿½ï¿½ï¿½ï¿½ñ£ï¿½îªê²ã´ï¿½ï¿½
������2��í¬ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ü¿ï¿½ï¿½îªï¿½ô¼ï¿½ï¿½ï¿½ï¿½ï¿½ê½ï¿½òµï¿½ï¿½ëºï¿½ï¿½êµï¿½ï¿½ï¿½ï¿½ñ£ï¿½ï¿½ï¿½ï¿½ï¿½ë����ê½ã»ï¿½ï¿½ï¿½òµï¿½ï¿½ï¿½ï¿½ñ£ï¿½ï¿½ï¿½ï¿½ü¸ï¿½ï¿½ý¸õ²ï¿½í¬ñ§ï¿½çµä·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ò»ï¿½ï¿½ï¿½ï¿½ï¿½êµäºï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½
加法交换律教学方法篇十一
������ñ§ä¿ï¿½ï¿½
����1����ñ§ï¿½ï¿½ï¿½ú¾ï¿½ï¿½ï¿½ì½ï¿½ï¿½ï¿½ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½éºí¼ó·ï¿½ï¿½ï¿½ï¿½ï¿½éµä¹ï¿½ï¿½ï¿½ï¿½ð£ï¿½ï¿½ï¿½ï¿½â²¢ï¿½ï¿½ï¿½õ¼ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½éºí¼ó·ï¿½ï¿½ï¿½ï¿½ï¿½é£ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½üµï¿½ó¦ï¿½ã¼ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½é¿ï¿½ï¿½ï¿½ê¹ò»ð©ï¿½ï¿½ï¿½ï¿½ï¿½ã¡£
����2����ì½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½éµä¹ï¿½ï¿½ï¿½ï¿½ð£ï¿½ï¿½ï¿½õ¹ñ§ï¿½ï¿½ï¿½ä·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½è½ï¡ï¿½ï¿½ï¿½ï¿½ó¡¢¸ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ ������ñ§ï¿½ï¿½ï¿½ä·ï¿½ï¿½å¸ð¡ï¿½
����3����ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ï¿½î¶¯ï¿½ð»ï¿½ã³é¹ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½é£¬ï¿½ï¿½ò»ï¿½ï¿½ï¿½ï¿½ç¿ï¿½ï¿½ï¿½ï¿½ñ§ñ§ï°ï¿½ï¿½ï¿½ï¿½è¤ï¿½ï¿½ï¿½ï¿½ï¿½ä£ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½î³é¶ï¿½ï¿½ï¿½ë¼ï¿½ï¿½ï¿½ï¿½ì½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ê¶ï¿½ï¿½ï°ï¿½ß¡ï¿½
������ñ§ï¿½øµï¿½
��������ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½é¡ï¿½
������ñ§ï¿½ñµï¿½
���������ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½é£ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ä¸ï¿½ï¿½ê¾ï¿½ï¿½
������ñ§ï¿½ï¿½ï¿½ï¿½
����������ñ§ï¿½ó·ï¿½ï¿½ï¿½ï¿½é¡ï¿½
����1���î¼ï¿½ï¿½ï¿½ê¾ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½í¬ñ§ï¿½ç¿ï¿½ï¿½ï¿½î¶¯ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ë�������������⣿����ñ§ï¿½ï¿½ï¿½ø´ï¿½ï¿½ï¿½ïµï¿½ï¿½ï¿½â½²ï¿½â£¬ï¿½ï¿½ï¿½ï¿½ï¿½é£º28+17=45���ë£ï¿½ï¿½ï¿½ï¿½ê£ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ë£º17+28=45���ë£ï¿½ï¿½ï¿½
����������ê½ï¿½ï¿½
����2���è½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ê½ï¿½ï¿½ê²ã´ï¿½ï¿½í¬ï¿½ï¿½
����3��������í¬ï¿½ï¿½ï¿½ï¿½ê½ï¿½ï¿½ï¿½ç¿ï¿½ï¿½ï¿½ï¿½ãµèºå°ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½éµï¿½ê½ï¿½ï¿½
����4��������������ëµï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½äµï¿½ê½ï¿½ï¿½ï¿½ô¼ï¿½ð´ò»ð´ï¿½ï¿½ñ§ï¿½ï¿½ëµï¿½ï¿½ï¿½ï¿½ê¦ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ê½ï¿½ï¿½ï¿½ï¿½×·ï¿½ê£ï¿½ï¿½ï¿½ï¿½ï¿½ò»ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ã´ð´ï¿½ä£ï¿½ï¿½ï¿½êµï¿½ç·ï¿½ï¿½ï¿½è¡ï¿½
����5���������é£ï¿½ï¿½ï¿½ï¸ï¿½û²ì£¬ï¿½ï¿½ê²ã´ï¿½ï¿½ï¿½é£ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ø´ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ö¹ï¿½ï¿½é¡ï¿½
����6�����ô¼ï¿½ï²ï¿½ï¿½ï¿½ä·ï¿½ê½ï¿½ï¿½ê¾ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½é£ï¿½ï¿½ï¿½ï¿½êµï¿½ï¿½ï¿½ê¾ï¿½ï¿½ï¿½ã·ï¿½ï¿½å¡ï¿½ï¿½ï¿½ï¿½ö¡ï¿½ï¿½ï¿½ä¸
����ñ§ï¿½ï¿½ë¼ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ö·ï¿½ï¿½ï¿½ï¿½ô¼ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ê¦ï¿½ï¿½ï¿½ï¿½ï¶ï¿½ï¿½ï¿½
����7����ñ§ï¿½ï£ï¿½ï¿½ï¿½ï¿½ï¿½ò»ï¿½ï¿½ï¿½ï¿½a��b��ê¾ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ð´ï¿½é£ï¿½a+b=b+a.��ê¦ð¡ï¿½á£º
�����������ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½é£ï¿½ï¿½ï¿½ï¿½é£©
����8��ð¡ï¿½ï¿½ï°ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½
����1�����é£ï¿½ï¿½õ²ï¿½ï¿½ï¿½ï¿½ï¿½ò»ï¿½ï¿½ï¿½ô£ï¿½ï¿½ï¿½ï¿½ëºü¶à·¢ï¿½ö£ï¿½ï¿½ï¿½ï¿½ï¿½æ²»ï¿½òµ¥¡ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ò»ï¿½ï¿½ï¿½ï¿½ï¿½â£¬ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ð©ï¿½õ»ñ£¿¿î¼ï¿½ï¿½ï¿½ê¾
����2����ê½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½×·ï¿½ï¿½ï¿½ï¿½ê½ï¿½ï¿½ï¿½å£¬ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½å±ï¿½ê¾ï¿½ï¿½ï¿½ã¡£ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ê²ã´ï¿½ï¿½ëµï¿½ï¿½ê½ï¿½ï¿½ï¿½ï¿½
����3���è½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ê½ï¿½ï¿½ï¿½ï¿½ê²ã´ï¿½ï¿½í¬ï¿½ï¿½ê²ã´ï¿½ï¿½í¬ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½îªê²ã´ï¿½ï¿½í¬ï¿½ï¿½ï¿½ï¿½ï¿½ç¿ï¿½ï¿½ï¿½ï¿½ãµèºï¿½ï¿½ï¿½ï¿½éµï¿½ê½ï¿½ï¿½
����4����ê¾ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ä¿ï¿½ï¿½ëµò»ëµï¿½ï¿½ï¿½ï¿½ò»ï¿½ã¡£
����5���������é£ï¿½ï¿½ï¿½ï¸ï¿½û²ì£¬ï¿½ï¿½ï¿½ï¿½ê²ã´ï¿½ï¿½ï¿½ö£ï¿½ñ§ï¿½ï¿½ï¿½ø´ð£¬½ï¿½ê¦ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ö¹ï¿½ï¿½é¡ï¿½
����6�����ü²ï¿½ï¿½ï¿½ï¿½ù¾ù¼ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ó£ï¿½ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½
����7����ê¦ð¡ï¿½á£¬ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ó·ï¿½ï¿½ï¿½ï¿½ï¿½é£ï¿½ï¿½ï¿½ï¿½é£©ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½a��b��c�ö±ï¿½ï¿½ê¾ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ó·ï¿½ï¿½ï¿½ï¿½ï¿½é¿ï¿½ï¿½ô±ï¿½ê¾ï¿½é£ï¿½
����8��ð¡ï¿½ï¿½ï°ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½
����1���õ²ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ï°ï¿½ë¼ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½éºí¼ó·ï¿½ï¿½ï¿½ï¿½ï¿½é£ï¿½ï¿½ï¿½ï¿½ç¶ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ú¼ó·ï¿½ï¿½ðµä¹ï¿½ï¿½é¡ï¿½ê¦ï¿½ü½á¡£
����2���îºï¿½ï¿½ï¿½ï°ï¿½ï¿½
������1�������ê½ï¿½ï¿½ó¦ï¿½ï¿½ï¿½ï¿½ê²ã´ï¿½ï¿½ï¿½ï¿½ï¿½é£ï¿½ñ§ï¿½ï¿½ëµò»ëµï¿½ï¿½ï¿½ôµï¿½ï¿½ï¿½ï¿½ï¿½ï¿½øµï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ã¡ï¿½
������2���è½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½éµï¿½ï¿½ï¿½ï¿½ã£ï¿½öªï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ù¡ï¿½
������3��������ð¡ï¿½ï¿½ï°ï¿½ï¿½
加法交换律教学方法篇十二
������ñ§ä¿ï¿½ï¿½
����1��ì½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½é£ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ã¡ï¿½
����2��������ñ§ï¿½ï¿½ï¿½ï¿½êµï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ïµï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ñ§öªê¶ï¿½ï¿½ï¿½ï¿½òµ¥µï¿½êµï¿½ï¿½ï¿½ï¿½ï¿½â¡£ ��ñ§ï¿½ø¡ï¿½ï¿½ñµï¿½
��������êµï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½é¾°ï¿½ð³ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½é¡ï¿½
������ñ§ï¿½ï¿½ï¿½ï¿½
����ò»ï¿½ï¿½ï¿½ï¿½è¤ï¿½ï¿½ñ§
����í¬ñ§ï¿½ï¿½ï²ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½æ¬ï¿½ï¿½ï¿½ï¿½ê¦ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ò»ï¿½ï¿½ð¡ï¿½ï¿½ï¿½ï¿½
����1������æ¬ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½äºï¿½ä¡ï¿½
����2������ë¼ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½öªï¿½ï¿½ï¿½ï¿½
���������������æ¬ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½í¬ñ§ï¿½ï¿½ëµð©ê²ã´ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ï¿½ð¦ï¿½ë£ï¿½ï¿½í½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ï¿½ð¦ê²ã´?������ëµï¿½ï¿½ï¿½ï¿½
����4+3=7������ 3+4=7�������î¼ï¿½ï¿½ï¿½ê¾
�����ê£ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ê½ï¿½ï¿½ê²ã´ï¿½ï¿½ïµ?(����������7������ê¾ï¿½ï¿½ï¿½ï¿½ò»ï¿½ï¿½ôµï¿½ï¿½ï¿½ï¿½ï¿½)����������ê½ö®ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ê²ã´ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ø£ï¿½ï¿½ï¿½ï¿½èºå£ï¿½
�����î¼ï¿½ï¿½ï¿½ê¾ï¿½ï¿½4+3=3+4
������������ì½ï¿½ï¿½ï¿½ï¿½ñ°ï¿½ò¹ï¿½ï¿½ï¿½
����1.������⣬���ö¹ï¿½ï¿½ï¿½
����ì¸ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½êµï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ß£ï¿½í¬ñ§ï¿½ç»ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ð£¿£ï¿½ï¿½á£©ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ò²ï¿½ï¿½ï¿½ï³µï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ò»ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½òªï¿½ï¿½ï¿½ç°ï¿½ã¦ï¿½ï¿½ï¿½ò»ï¿½â¡ï¿½ �î¼ï¿½ï¿½ï¿½ê¾ï¿½ï³µï¿½ï¿½ï¿½ï¿½í¼ï¿½ï¿½
�����ê£ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ôµãµï¿½ï¿½ï¿½ð©ï¿½ï¿½ï¢ï¿½ï¿½òªï¿½ï¿½ê²ã´ï¿½ø£ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½40ç§ï¿½×£ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½56ç§ï¿½×£ï¿½ï¿½ï¿½ï¿½ï¿½ò»ï¿½ï¿½ï¿½ï¿½ï¿½ë¶ï¿½ï¿½ï¿½ç§ï¿½×£ï¿½ï¿½ï¿½
�����ê£ï¿½ò»ï¿½ï¿½ï¿½ï¿½ï¿½ë¶ï¿½ï¿½ï¿½ç§ï¿½×£ï¿½ï¿½ï¿½ï¿½ï¿½ê½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ð£¿£ï¿½ï¿½ü£ï¿½
�������ú²ý¸å±¾ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ê¦ï¿½ï¿½è¥ï¿½òµï¿½ï¿½ï¿½òªï¿½ä´ð°¸£ï¿½ï¿½ï¿½ï¿½ï¿½ú°å¡£
����40+56=96��ç§ï¿½×£ï¿½56+40=96��ç§ï¿½×£ï¿½
�����ê£ï¿½ï¿½û²ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½í¬ñ§ï¿½ï¿½ï¿½ï¿½ê½ï¿½ï¿½ï¿½ï¿½ï¿½ç·ï¿½ï¿½ï¿½ï¿½ï¿½ê²ã´ï¿½ï¿½
����������ê½ï¿½ï¿½ï¿½ï¿½ä½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ò»ï¿½ï¿½ï¿½ä£ï¿½ï¿½ï¿½ï¿½ç¿ï¿½ï¿½ï¿½ï¿½ãµèºï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½
�����î¼ï¿½ï¿½ï¿½ê¾40+56=96��ç§ï¿½×£ï¿½56+40=96��ç§ï¿½×£ï¿½
����40+56=56+40
����2.�������룬��������
�����î¼ï¿½ï¿½ï¿½ê¾4+3=3+440+56=56+40
�����û²ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ê½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ß¼ï¿½ï¿½ï¿½ä½ï¿½ï¿½ï¿½ï¿½è£ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ãµèºï¿½ï¿½ï¿½ï¿½ó£ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ù¾ù³ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½í¬ï¿½ï¿½ï¿½ï¿½ï¿½à½»ï¿½ï¿½ï¿½ï¿½
����è«ï¿½à½»ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ä»ã±¨ï¿½ï¿½ï¿½ð´ï¿½úºú°ï¿½ï¿½ï¡ï¿½
����í¬ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ã´ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ó£ï¿½ï¿½ï¿½ï¿½ü·ï¿½ï¿½ï¿½ê²ã´ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ä»ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ í¬ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½
����è«ï¿½à½»ï¿½ï¿½ï¿½ï¿½ï¿½ü½ï¿½ï¿½ï¿½é£ºï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½î»ï¿½ã£ï¿½ï¿½í²ï¿½ï¿½ä¡£
�����ê£ï¿½ï¿½ï¿½ï¿½ü¸ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ð£¿£ï¿½ï¿½ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½é£ï¿½
�����ò°ñ¼ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½é»ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ê¦ï¿½ï¿½ï¿½ï¿½ï¿½ð¼ï¿½ï¿½ï¿½ï¿½ï¿½ê½ �î¼ï¿½ï¿½ï¿½ê¾ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½
������ 30+20 ��î»ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½î»ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½î»ï¿½ã£ï¿½ï¿½ï¿½ï¿½ç²ï¿½ï¿½ï¿½
������ 100+30 ��î»ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½î»ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½î»ï¿½ã£ï¿½ï¿½ï¿½ò²ï¿½ç²ï¿½ï¿½ï¿½
������ 1000+200 ��î»ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½î»ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½î»ï¿½ã£ï¿½ï¿½í»ï¿½ï¿½ç²ï¿½ï¿½ï¿½
�����õ²å¾ï¿½ï¿½ï¿½í¬ñ§ï¿½çµï¿½å¬ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ç·ï¿½ï¿½ï¿½ï¿½ë²ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ê²ã´ï¿½ï¿½ö»òªï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½î»ï¿½ã£ï¿½ï¿½ï¿½ï¿½çµäºí²ï¿½ï¿½ä¡£ï¿½ï¿½ï¿½ç°ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½é½ï¿½ï¿½ï¿½ï¿½ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½é¡ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½é£ºï¿½ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½é£ï¿½ï¿½î¼ï¿½ï¿½ï¿½ê¾ï¿½ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½éµï¿½ï¿½ï¿½ï¿½ý¡ï¿½
����3.��ï²ï¿½ï¿½ï¿½ä·ï¿½ê½ï¿½ï¿½ê¾ï¿½ï¿½ï¿½ï¿½
����������ê¾ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ó£ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½î»ï¿½ãºí²ï¿½ï¿½ï¿½ï¿½ø£ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ô¼ï¿½ï²ï¿½ï¿½ï¿½ä·ï¿½ê½ï¿½ï¿½ê¾ï¿½ï¿½
������í¬ñ§ï¿½ï¿½ï¿½à»¥ï¿½ï¿½ï¿½û£ï¿½ï¿½ï¿½ê¦ï¿½ï¿½è¥ï¿½ï¿½ï¿½ï¿½í¬ñ§
����è«ï¿½à½»ï¿½ï¿½ �뷨ò»ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½+����=����+����
�����뷨������+��=��+��
�����뷨����a+b=b+a
����ê¦ï¿½ï¿½í¬ñ§ï¿½ç¸ï¿½ï¿½ã¼ºï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ã´ï¿½ï¿½ä·ï¿½ê½ï¿½ï¿½ê¾ï¿½ï¿½í¬ñ§ï¿½ç¾ï¿½ï¿½ï¿½ï¿½ï¿½ò»ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½?îªê²ã´ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ë¡ï¿½ï¿½ï¿½
�����î¼ï¿½ï¿½ï¿½ê¾ï¿½ï¿½a+b=b+a
����ì¸ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½öªï¿½ï¿½ï¿½ë¼ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½é£ï¿½ï¿½ï¿½ï¿½ò»ï¿½ï¿½ï¿½ï¿½ô¼ï¿½ï²ï¿½ï¿½ï¿½ä·ï¿½ê½ï¿½ï¿½ê¾ï¿½ï¿½ï¿½ï¿½í¬ñ§ï¿½ï¿½ï¿½ï¿½ò»ï¿½ë£¬ï¿½ï¿½ç°ñ§ï¿½ï¿½ï¿½ï¿½öªê¶ï¿½ð£ï¿½ï¿½ï¿½ð©ï¿½ø·ï¿½ï¿½ãµï¿½ï¿½ï¿½ï¿½ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½é£ï¿½ï¿½ï¿½ï¿½ï¿½ó·ï¿½ê±ï¿½ï¿½
�����î¼ï¿½ï¿½ï¿½ê¾876+1924
����4.ë¼ï¿½ï¿½ï¿½â£¬ï¿½ï¿½õ¹ï¿½ï¿½ï¿½ï¿½
�������������ê½ó¦ï¿½ï¿½ï¿½ë¼ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½
�����î¼ï¿½ï¿½ï¿½ê¾3+4+5=4+3+5
������������������棬����ò²ï¿½ï¿½ï¿½ï¿½ï¿½ã¼ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½
�������ã¼ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½é£ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½êµï¿½ï¿½ï¿½ï¿½ï¿½
����355��423��423������
����258���� �� ��340������
����a��268��268+�� ��
����35+42+65=35+()+( )
�����ü½á£ºï¿½ï¿½ú¿ï¿½ï¿½ï£ï¿½í¬ñ§ï¿½ç¸ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ö¶ï¿½ï¿½ü°ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ë¼ï¿½ï¿½ï¿½ï¿½ó»ô¾ï¿½ø´ï¿½ï¿½ï¿½ï¿½â£¬ñ§ï°ï¿½ï¿½ï¿½é²»ï¿½ï¸ï¿½ï¿½ç£ï¿½ï¿½ï¿½ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ü½ï¿½ä¹ï¿½ï¿½é£ï¿½ï¿½ï¿½ï¿½ï¿½ò²ï¿½ü·ï¿½ï¿½ö£ï¿½í¬ñ§ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ò»ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ì½ï¿½ï¿½ï¿½ó·ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½éµä¹ï¿½ï¿½ì£ï¿½ï¿½ï¿½ï¿½ï¿½ê²ã´ï¿½õ»ï¿½ï¿½ø£ï¿½