发布人:张云凤
所在工作坊: 勐腊镇小学 小学数学
时间日期:2018-12-18 至 2018-12-31
101讨论 35人
<p>集体备课人教版四年级数学下册《四则运算——加法交换律》教案。</p>
开始时间 : 2018-12-18结束时间 : 2018-12-31
步骤描述: <p style="text-align:center"><span style=";font-family:宋体;font-size:19px"><span style="font-family:宋体">人教版</span></span><span style=";font-family:'Times New Roman';font-size:19px"><span style="font-family:宋体">四年级</span></span><span style=";font-family:宋体;font-size:19px"><span style="font-family:宋体">数学</span></span><span style=";font-family:'Times New Roman';font-size:19px"><span style="font-family:宋体">下册《加法交换律》教学设计</span></span></p><p style="margin-left:19px;text-align:justify;text-justify:inter-ideograph"><span style=";font-family:'Times New Roman';font-size:19px"><span style="font-family:宋体">【教学理念】</span></span></p><p style="margin-left:19px;text-indent:19px;text-align:justify;text-justify:inter-ideograph"><span style=";font-family:'Times New Roman';font-size:19px"><span style="font-family:宋体">以学生为主体,教师为主导,以观察比较为主线,以师生互动、</span></span></p><p style="text-align:justify;text-justify:inter-ideograph"><span style=";font-family:'Times New Roman';font-size:19px"><span style="font-family:宋体">生生互动,自主探索,分组讨论交流为主要方式。让数学贴近实际,贴近生活,贴近原有经验。使学生主动学数学,探究学数学,快乐学数学</span></span><span style=";font-family:宋体;font-size:19px"><span style="font-family:宋体">,</span></span><span style=";font-family:'Times New Roman';font-size:19px"><span style="font-family:宋体">并进一步促进学生思维的发展。</span> </span></p><p style="margin-left:19px;text-align:justify;text-justify:inter-ideograph"><span style=";font-family:'Times New Roman';font-size:19px"><span style="font-family:宋体">【教学内容】</span></span></p><p style="margin-left:19px;text-indent:19px;text-align:justify;text-justify:inter-ideograph"><span style=";font-family:'Times New Roman';font-size:19px"><span style="font-family:宋体">四年级下册第</span>17<span style="font-family:宋体">页例</span><span style="font-family:Times New Roman">1 </span><span style="font-family:宋体">练习五 第</span><span style="font-family:Times New Roman">2</span><span style="font-family:宋体">题 </span></span></p><p style="margin-left:19px;text-align:justify;text-justify:inter-ideograph"><span style=";font-family:'Times New Roman';font-size:19px"><span style="font-family:宋体">【教学目标】</span></span><span style=";font-family:'Times New Roman';font-size:19px"><br/></span><span style=";font-family:'Times New Roman';font-size:19px">1<span style="font-family:宋体">探索和理解加法交换律,并能够用字母表示加法交换律。</span></span><span style=";font-family:'Times New Roman';font-size:19px"><br/></span><span style=";font-family:'Times New Roman';font-size:19px">2 <span style="font-family:宋体">在学习用符号、字母表示自己发现的运算定律的过程中,培养符号感和推理能力,逐步提高抽象思维能力。</span></span><span style=";font-family:'Times New Roman';font-size:19px"><br/></span><span style=";font-family:'Times New Roman';font-size:19px">3.<span style="font-family:宋体">经历探索加法交换律的过程,通过对熟悉的实际问题的解决,进行比较和分析,发现并概括交换律。</span></span><span style=";font-family:'Times New Roman';font-size:19px"><br/></span><span style=";font-family:'Times New Roman';font-size:19px">4.<span style="font-family:宋体">在数学活动中获得成功的体验,进一步增强学习数学的信心,培养独立思考和探究问题的意识和习惯</span></span></p><p style="margin-left:19px;text-align:justify;text-justify:inter-ideograph"><span style=";font-family:'Times New Roman';font-size:19px"><span style="font-family:宋体">【教学重难点】掌握加法交换律,并会运用加法交换律进行计算。</span></span></p><p style="margin-left:19px;text-align:justify;text-justify:inter-ideograph"><span style=";font-family:'Times New Roman';font-size:19px"><span style="font-family:宋体">【教学过程】</span></span><span style=";font-family:'Times New Roman';font-size:19px"><br/></span><span style=";font-family:'Times New Roman';font-size:19px"><span style="font-family:宋体">一、</span> <span style="font-family:宋体">创设情境,生成问题。</span></span><span style=";font-family:'Times New Roman';font-size:19px"><br/></span><span style=";font-family:'Times New Roman';font-size:19px">1<span style="font-family:宋体">、下面老师想给大家讲一个故事,好吗?但是,老师有一个小小的要求:请大家边听边思考,你从中发现了什么?</span></span><span style=";font-family:'Times New Roman';font-size:19px"><br/></span><span style=";font-family:'Times New Roman';font-size:19px"><span style="font-family:宋体">讲故事</span> </span><span style=";font-family:宋体;font-size:19px"><span style="font-family:宋体">:</span></span><span style=";font-family:'Times New Roman';font-size:19px"><span style="font-family:宋体">宋朝有一个很喜欢饲养猴子的人,人们叫他狙公。他家养了一大群猴子,他能理解猴子的意思,猴子也懂得他的心意。他宁可减少全家的食用,也要满足猴子的要求。然而过了不久,家里越来越穷困了,他不得不减少猴子的食量。有一天,他对猴子说:</span>“<span style="font-family:宋体">早上,我给你们每只猴子三个桃子;晚上,我给你们每只猴子四个桃子。你们够吃吗?</span><span style="font-family:Times New Roman">”</span><span style="font-family:宋体">猴子们一听,十分恼怒,都不同意。 于是,他想了想,又说:</span><span style="font-family:Times New Roman">“</span><span style="font-family:宋体">这样吧。早上,我给你们每只猴子四个桃子;晚上,给你们每只猴子三个。这下总该够吃了吧?</span><span style="font-family:Times New Roman">”</span><span style="font-family:宋体">猴子们一听,一个个趴在地上,非常高兴。</span></span><span style=";font-family:'Times New Roman';font-size:19px"><br/></span><span style=";font-family:'Times New Roman';font-size:19px">2<span style="font-family:宋体">、故事讲完了,你发现了什么?</span></span><span style=";font-family:'Times New Roman';font-size:19px"><br/></span><span style=";font-family:'Times New Roman';font-size:19px"><span style="font-family:宋体">(不论是早上给</span>3<span style="font-family:宋体">个桃子,晚上给</span><span style="font-family:Times New Roman">4</span><span style="font-family:宋体">个桃子;还是早上给</span><span style="font-family:Times New Roman">4</span><span style="font-family:宋体">个桃子,晚上给</span><span style="font-family:Times New Roman">3</span><span style="font-family:宋体">个桃子。都一样,都是一共</span><span style="font-family:Times New Roman">7</span><span style="font-family:宋体">个桃子。)</span></span><span style=";font-family:'Times New Roman';font-size:19px"><br/></span><span style=";font-family:'Times New Roman';font-size:19px">3<span style="font-family:宋体">、你能用算式表示吗?</span></span><span style=";font-family:'Times New Roman';font-size:19px"><br/></span><span style=";font-family:'Times New Roman';font-size:19px"><span style="font-family:宋体">(学生列式,老师板书:</span>3+4 4+3<span style="font-family:宋体">) </span></span><span style=";font-family:'Times New Roman';font-size:19px"><br/></span><span style=";font-family:'Times New Roman';font-size:19px">4<span style="font-family:宋体">、这两道算式都等于</span><span style="font-family:Times New Roman">7</span><span style="font-family:宋体">,那么它们之间可以用什么符号连接呢?</span></span><span style=";font-family:'Times New Roman';font-size:19px"><br/></span><span style=";font-family:'Times New Roman';font-size:19px"><span style="font-family:宋体">(等号)(学生回答,老师板书:</span>3+4=4+3<span style="font-family:宋体">)</span></span></p><p style="margin-left:19px;text-align:justify;text-justify:inter-ideograph"><span style=";font-family:'Times New Roman';font-size:19px"><span style="font-family:宋体">【设计理念:俗话说,好的开始是成功的一半,我没有利用书中的主题图,而是选择了更加贴近学生的成语故事</span>“<span style="font-family:宋体">朝三暮四</span><span style="font-family:Times New Roman">”</span><span style="font-family:宋体">,一下子抓住学生的兴趣和注意力,让学生初步感知加法交换律。同时培养学生认真倾听的良好学习习惯。】 </span></span><span style=";font-family:'Times New Roman';font-size:19px"><br/></span><span style=";font-family:'Times New Roman';font-size:19px">5<span style="font-family:宋体">、其实我们生活中有许许多多的例子反映了同样的道理。</span></span><span style=";font-family:'Times New Roman';font-size:19px"><br/></span><span style=";font-family:'Times New Roman';font-size:19px"><span style="font-family:宋体">二、</span> <span style="font-family:宋体">探索交流,解决问题</span></span><span style=";font-family:'Times New Roman';font-size:19px"><br/></span><span style=";font-family:'Times New Roman';font-size:19px">1<span style="font-family:宋体">、出示题目</span></span><span style=";font-family:'Times New Roman';font-size:19px"><br/></span><span style=";font-family:'Times New Roman';font-size:19px"><span style="font-family:宋体">(</span>1<span style="font-family:宋体">)从题中我们可以知道哪些数学信息?</span></span><span style=";font-family:'Times New Roman';font-size:19px"><br/></span><span style=";font-family:'Times New Roman';font-size:19px"><span style="font-family:宋体">(</span>2<span style="font-family:宋体">)要我们解决的问题是什么?</span></span></p><p style="margin-left:19px;text-align:justify;text-justify:inter-ideograph"><span style=";font-family:'Times New Roman';font-size:19px"><span style="font-family:宋体">【设计理念:通过此环节的教学,培养学生发现和提出问题的能力,分析和解决问题的能力。】</span></span><span style=";font-family:'Times New Roman';font-size:19px"><br/></span><span style=";font-family:'Times New Roman';font-size:19px">2<span style="font-family:宋体">、弄清了题意,我们再来思考一下:</span></span><span style=";font-family:'Times New Roman';font-size:19px"><br/></span><span style=";font-family:'Times New Roman';font-size:19px"><span style="font-family:宋体">(让学生列出两种不同的算式,同桌之间互相交流评论)</span></span><span style=";font-family:'Times New Roman';font-size:19px"><br/></span><span style=";font-family:'Times New Roman';font-size:19px">40<span style="font-family:宋体">+</span><span style="font-family:Times New Roman">56=96</span><span style="font-family:宋体">(千米) </span><span style="font-family:Times New Roman">56</span><span style="font-family:宋体">+</span><span style="font-family:Times New Roman">40=96</span><span style="font-family:宋体">(千米)</span></span><span style=";font-family:'Times New Roman';font-size:19px"><br/></span><span style=";font-family:'Times New Roman';font-size:19px">3<span style="font-family:宋体">、教师提问:这两个算式有什么联系?</span></span><span style=";font-family:'Times New Roman';font-size:19px"><br/></span><span style=";font-family:'Times New Roman';font-size:19px"><span style="font-family:宋体">(得数都等于</span>96<span style="font-family:宋体">,都表示李叔叔一天的总行程。)</span></span><span style=";font-family:'Times New Roman';font-size:19px"><br/></span><span style=";font-family:'Times New Roman';font-size:19px"><span style="font-family:宋体">这两个算式之间可以用什么数学符号连接起来呢?(学生讨论回答。)</span></span><span style=";font-family:'Times New Roman';font-size:19px"><br/></span><span style=";font-family:'Times New Roman';font-size:19px">4<span style="font-family:宋体">、你还能再举出几个这样的例子吗?(教师根据学生的回答板书。)</span></span><span style=";font-family:'Times New Roman';font-size:19px"><br/></span><span style=";font-family:'Times New Roman';font-size:19px">37<span style="font-family:宋体">+</span><span style="font-family:Times New Roman">45=45</span><span style="font-family:宋体">+</span><span style="font-family:Times New Roman">37 89</span><span style="font-family:宋体">+</span><span style="font-family:Times New Roman">78=78</span><span style="font-family:宋体">+</span><span style="font-family:Times New Roman">89 </span></span><span style=";font-family:'Times New Roman';font-size:19px"><br/></span><span style=";font-family:'Times New Roman';font-size:19px">53<span style="font-family:宋体">+</span><span style="font-family:Times New Roman">98=98</span><span style="font-family:宋体">+</span><span style="font-family:Times New Roman">53 873</span><span style="font-family:宋体">+</span><span style="font-family:Times New Roman">127=127</span><span style="font-family:宋体">+</span><span style="font-family:Times New Roman">873</span></span></p><p style="margin-left:19px;text-align:justify;text-justify:inter-ideograph"><span style=";font-family:'Times New Roman';font-size:19px"><span style="font-family:宋体">【设计理念:通过此环节的教学,使学生发挥了自己的思维进行举例,调动了学生的积极性和主动性。】</span></span><span style=";font-family:'Times New Roman';font-size:19px"><br/></span><span style=";font-family:'Times New Roman';font-size:19px">5<span style="font-family:宋体">、教师提问:这四组算式有什么特点?你发现了什么规律?</span></span><span style=";font-family:'Times New Roman';font-size:19px"><br/></span><span style=";font-family:'Times New Roman';font-size:19px"><span style="font-family:宋体">(引导学生分组讨论交流,在汇报时,引导学生从和的大小与加数的顺序进行回答,并鼓励学生用自己的语言说一说。)</span></span><span style=";font-family:'Times New Roman';font-size:19px"><br/></span><span style=";font-family:'Times New Roman';font-size:19px">6<span style="font-family:宋体">、小结:大家发现的规律叫做加法交换律。(板书:两个加数交换位置,和不变。)</span></span></p><p style="margin-left:19px;text-align:justify;text-justify:inter-ideograph"><span style=";font-family:'Times New Roman';font-size:19px"><span style="font-family:宋体">【设计理念:引导学生自我总结规律,培养学生的概括推理能力。】</span></span><span style=";font-family:'Times New Roman';font-size:19px"><br/></span><span style=";font-family:'Times New Roman';font-size:19px">7<span style="font-family:宋体">、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?试试用你喜欢的符号表示两个加数,你能用式子表示加法交换律吗?</span></span><span style=";font-family:'Times New Roman';font-size:19px"><br/></span><span style=";font-family:'Times New Roman';font-size:19px"><span style="font-family:宋体">(教师根据学生的回答板书:甲数+乙数</span>=<span style="font-family:宋体">乙数+甲数</span></span><span style=";font-family:'Times New Roman';font-size:19px"><br/></span><span style=";font-family:'Times New Roman';font-size:19px">a<span style="font-family:宋体">+</span><span style="font-family:Times New Roman">b=b</span><span style="font-family:宋体">+</span><span style="font-family:Times New Roman">a □</span><span style="font-family:宋体">+</span></span><span style=";font-family:宋体;font-size:19px">△</span><span style=";font-family:'Times New Roman';font-size:19px">=</span><span style=";font-family:宋体;font-size:19px">△</span><span style=";font-family:'Times New Roman';font-size:19px"><span style="font-family:宋体">+</span>□<span style="font-family:宋体">)</span></span><span style=";font-family:'Times New Roman';font-size:19px"><br/></span><span style=";font-family:'Times New Roman';font-size:19px">8<span style="font-family:宋体">、大家比较一下所有的表达方式,哪个表达方式最简单呢?(使学生明确,用字母表达方式最简单。)</span></span><span style=";font-family:'Times New Roman';font-size:19px"><br/></span><span style=";font-family:'Times New Roman';font-size:19px">9<span style="font-family:宋体">、字母式子告诉我们什么?</span></span><span style=";font-family:'Times New Roman';font-size:19px"><br/></span><span style=";font-family:'Times New Roman';font-size:19px"><span style="font-family:宋体">(任意两个数相加,交换位置,和不变。)</span></span></p><p style="margin-left:19px;text-align:justify;text-justify:inter-ideograph"><span style=";font-family:'Times New Roman';font-size:19px"><span style="font-family:宋体">【设计理念:用自己喜欢的符号表示加法交换律,最后通过比较得出用数学语言表达最准确,这样充分地发挥了学生在数学学习中的主体地位。】</span></span><span style=";font-family:'Times New Roman';font-size:19px"><br/></span><span style=";font-family:'Times New Roman';font-size:19px"><span style="font-family:宋体">三、</span> <span style="font-family:宋体">巩固应用,内化提高。</span></span><span style=";font-family:'Times New Roman';font-size:19px"><br/></span><span style=";font-family:'Times New Roman';font-size:19px">1.<span style="font-family:宋体">基本应用。</span></span><span style=";font-family:'Times New Roman';font-size:19px"><br/></span><span style=";font-family:'Times New Roman';font-size:19px"><span style="font-family:宋体">引导学生完成教材第</span>28<span style="font-family:宋体">页</span><span style="font-family:Times New Roman">“</span><span style="font-family:宋体">做一做</span><span style="font-family:Times New Roman">”</span><span style="font-family:宋体">,然后汇报交流。</span></span></p><p style="margin-left:19px;text-align:justify;text-justify:inter-ideograph"><span style=";font-family:'Times New Roman';font-size:19px"><span style="font-family:宋体">【设计理念:体现了知识的目的性。】</span></span><span style=";font-family:'Times New Roman';font-size:19px"><br/></span><span style=";font-family:'Times New Roman';font-size:19px">2<span style="font-family:宋体">、巩固练习。</span></span><span style=";font-family:'Times New Roman';font-size:19px"><br/></span><span style=";font-family:'Times New Roman';font-size:19px"><span style="font-family:宋体">完成教材第</span>31<span style="font-family:宋体">页的练习五第</span><span style="font-family:Times New Roman">1</span><span style="font-family:宋体">至第</span><span style="font-family:Times New Roman">3</span><span style="font-family:宋体">题。</span></span></p><p style="margin-left:19px;text-align:justify;text-justify:inter-ideograph"><span style=";font-family:'Times New Roman';font-size:19px"><span style="font-family:宋体">【设计理念:体现了知识的层次性。同时,也培养了学生养成验算的良好习惯】</span></span><span style=";font-family:'Times New Roman';font-size:19px"><br/></span><span style=";font-family:'Times New Roman';font-size:19px">3 <span style="font-family:宋体">深化练习</span></span><span style=";font-family:'Times New Roman';font-size:19px"><br/></span><span style=";font-family:'Times New Roman';font-size:19px">25<span style="font-family:宋体">+( )</span><span style="font-family:Times New Roman">=75</span><span style="font-family:宋体">+( )</span></span><span style=";font-family:宋体;font-size:19px"> </span><span style=";font-family:'Times New Roman';font-size:19px">56<span style="font-family:宋体">+</span><span style="font-family:Times New Roman">144=</span><span style="font-family:宋体">( )+( )</span></span><span style=";font-family:'Times New Roman';font-size:19px"><br/></span><span style=";font-family:'Times New Roman';font-size:19px">36<span style="font-family:宋体">+( )</span><span style="font-family:Times New Roman">=64</span><span style="font-family:宋体">+( )</span></span><span style=";font-family:宋体;font-size:19px"> </span><span style=";font-family:'Times New Roman';font-size:19px">a<span style="font-family:宋体">+( )</span><span style="font-family:Times New Roman">=12</span><span style="font-family:宋体">+( )</span></span></p><p style="margin-left:19px;text-align:justify;text-justify:inter-ideograph"><span style=";font-family:'Times New Roman';font-size:19px"><span style="font-family:宋体">【设计理念:通过练习这个环节的教学,使学生巩固了对加法交换律的认识。使学生能够灵活地运用加法交换律进行计算】</span></span><span style=";font-family:'Times New Roman';font-size:19px"><br/></span><span style=";font-family:'Times New Roman';font-size:19px"><span style="font-family:宋体">四</span> <span style="font-family:宋体">、回顾整理,反思提升。</span></span><span style=";font-family:'Times New Roman';font-size:19px"><br/></span><span style=";font-family:'Times New Roman';font-size:19px"><span style="font-family:宋体">今天我们学习了什么?你懂得了些什么?</span></span></p><p style="margin-left:19px;text-align:justify;text-justify:inter-ideograph"><span style=";font-family:'Times New Roman';font-size:19px"><span style="font-family:宋体">【设计理念:以谈收获的谈话对节课所学的知识进行梳理,有利于学生加深理解,培养了学生的语言表达能力和综合概括能力。】</span></span></p><p style="margin-left:19px;text-align:justify;text-justify:inter-ideograph"><span style="font-family: 宋体; font-size: 19px;">【板书设计】 </span><strong><span style="font-family: 'Times New Roman';font-size: 19px"><span style="font-family:宋体">加法交换律</span></span></strong></p><p style="margin-left:19px;text-align:justify;text-justify:inter-ideograph"><span style="font-family: 宋体; font-size: 19px;"><strong> </strong>两个加数交换位置,和不变</span></p><p style="margin-left:243px;text-align:justify;text-justify:inter-ideograph"><span style=";font-family:'Times New Roman';font-size:19px"><span style="font-family:宋体">甲数+乙数</span>=<span style="font-family:宋体">乙数+甲数 </span></span></p><p style="margin-left:243px;text-align:justify;text-justify:inter-ideograph"><span style=";font-family:'Times New Roman';font-size:19px">□<span style="font-family:宋体">+</span></span><span style=";font-family:宋体;font-size:19px">△</span><span style=";font-family:'Times New Roman';font-size:19px">=</span><span style=";font-family:宋体;font-size:19px">△</span><span style=";font-family:'Times New Roman';font-size:19px"><span style="font-family:宋体">+</span>□</span></p><p style="margin-left:243px;text-align:justify;text-justify:inter-ideograph"><span style="font-family: "Times New Roman"; font-size: 19px;">a<span style="font-family:宋体">+</span>b=b<span style="font-family:宋体">+</span>a</span></p><p style="margin-left:243px;text-align:justify;text-justify:inter-ideograph"><br/></p><p><br/></p>
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