长方形和正方形周长的计算方法

《长方形和正方形周长的计算方法》 教 学 设 计 学 院 教育科学学院 专 业 09级教育 姓 名 李 冬 梅 学 号 2009310382 to achieve high quality project. 5. instrument installation construction alternatives 5.1 5.1.1 the instrument construction methods General requirements 5.1.1.1 to ensure smooth instrument construction, instrument technician prior to construction workers, have a thorough check, calculate construction materials and technology to give the low-down the construction workers. 5.1.1.2 closely linked to pipeline construction of the instrument unit, with the active cooperation, so as to avoid the instrument device is not properly installed and rework and, if necessary, corresponding with the related technical or construction plan key single equipment prior to commissioning, shall report the test application by party representatives, representatives of the management company and the factory specialists is confirmed, in order to perform. 5.1.1.3 strictly quality inspection system, each process was finished, filled in by the workers, technicians and construction quality inspection requests, advance written notice to the management company site engineer and QC personnel, make conclusions on construction quality in the future, quality form a basis of the project when completed. 5.1.1.4 strictly professional transfer of process quality inspection system, handling written delivery list. The transfer of professional process, must be fully installed quality inspection processes installed on disqualification, shall not be carried out the next working procedure operation; important instrumentation engineering processes must inform the management company engineers check and a written record. 5.1.1.5 strictly abide by the national regulation and construction site safety regulations to ensure 长方形和正方形周长的计算方法 一、 教材分析 《长方形和正方形周长的计算方法》是人教版三年级数学(P42—P43)。本课教学内容是在学生理解周长概念的基础上进行教学的，有两个例题和做一做的题。例1是求长方形卡片的周长，例2是求正方卡片的周长，引导学生探索并掌握长方形和正方形周长的计算方法，能正确计算长方形和正方形的周长，为以后学习正方体、长方体的表面积做铺垫。 教学重点: 1. 使学生进一步理解周长的概念。 2. 通过理解、亲身操作体验，掌握长方形和正方形周长的计算 方法，并能准确计算，获得成功体验。 教学难点: 要求同学会用多种方法计算长方形和正方形的周长。(可以根据学生自身的条件，尽量多掌握计算方法，每人至少要掌握一种适合自己的计算方法)。 二、 学情分析 学生已经对周长有了初步的认识，也能够用直尺、绳缠等方法算出各种封闭图形的周长，只能靠测量的方法来求解。本节课所讲的内容是对特殊图形长方形和正方形的周长求解，所以在教学的过程中举一些与生活实际相关的例子，从实际生活入手，运用周长的to achieve high quality project. 5. instrument installation construction alternatives 5.1 5.1.1 the instrument construction methods General requirements 5.1.1.1 to ensure smooth instrument construction, instrument technician prior to construction workers, have a thorough check, calculate construction materials and technology to give the low-down the construction workers. 5.1.1.2 closely linked to pipeline construction of the instrument unit, with the active cooperation, so as to avoid the instrument device is not properly installed and rework and, if necessary, corresponding with the related technical or construction plan key single equipment prior to commissioning, shall report the test application by party representatives, representatives of the management company and the factory specialists is confirmed, in order to perform. 5.1.1.3 strictly quality inspection system, each process was finished, filled in by the workers, technicians and construction quality inspection requests, advance written notice to the management company site engineer and QC personnel, make conclusions on construction quality in the future, quality form a basis of the project when completed. 5.1.1.4 strictly professional transfer of process quality inspection system, handling written delivery list. The transfer of professional process, must be fully installed quality inspection processes installed on disqualification, shall not be carried out the next working procedure operation; important instrumentation engineering processes must inform the management company engineers check and a written record. 5.1.1.5 strictly abide by the national regulation and construction site safety regulations to ensure 知识来解决一些现实生活中的问题，使学生主动参与到教学活动中，更好的掌握求长方形和正反形周长的方法。 三、 教学目标 1.能够说出长方形和正方形周长的计算及其推导过程。 2.学会运用多种方法计算长方形和正方形的周长。 3.培养初步的空间观念及其自己动手操作的能力，经过学生之间的 讨论，培养学生独立探究、独立思考能力、合作交流学习能力。 4.体验主动获取新知识的成就感。体会运用新知识解决实际问题的 愉悦 ，培养学生学习的好习惯。 四、教学策略 教学方法: 1. 采取小组合作，自己动手操作，引导学生发现长方形和正方形 周长的计算方法。 2. 情景法:整节课都是围绕着开头那个故事谁用的绳子长来 展开的，使学生体会到数学与生活紧密联系，生活处处离不开 数学。也培养学生团队的合作精神，运用数学的知识解决生活 中的实际问题。 课前准备: 1. 每名同学准备相同规格的长方形和正方形等学具。 2. 多媒体课件。 3. 格尺、线绳等测量工具。 五、 教学过程 to achieve high quality project. 5. instrument installation construction alternatives 5.1 5.1.1 the instrument construction methods General requirements 5.1.1.1 to ensure smooth instrument construction, instrument technician prior to construction workers, have a thorough check, calculate construction materials and technology to give the low-down the construction workers. 5.1.1.2 closely linked to pipeline construction of the instrument unit, with the active cooperation, so as to avoid the instrument device is not properly installed and rework and, if necessary, corresponding with the related technical or construction plan key single equipment prior to commissioning, shall report the test application by party representatives, representatives of the management company and the factory specialists is confirmed, in order to perform. 5.1.1.3 strictly quality inspection system, each process was finished, filled in by the workers, technicians and construction quality inspection requests, advance written notice to the management company site engineer and QC personnel, make conclusions on construction quality in the future, quality form a basis of the project when completed. 5.1.1.4 strictly professional transfer of process quality inspection system, handling written delivery list. The transfer of professional process, must be fully installed quality inspection processes installed on disqualification, shall not be carried out the next working procedure operation; important instrumentation engineering processes must inform the management company engineers check and a written record. 5.1.1.5 strictly abide by the national regulation and construction site safety regulations to ensure (一) 故事导入，揭示课题 1.同学们，有一天，小狗和小兔为了一件事发生了争吵。怎么一回事呢,原来，小狗用绳子围成了一个正方形，小兔用绳子围成了一个长方形。小兔说:我用的绳子长，小狗说，我的绳子比你的长。同学们，你们能有什么办法判断谁的绳子长一点，谁的短一点呢, 2.学生思考，出主意。其实，我们要比较“围成两个图形所用绳子的长短就是要比较两个图形的周长”那我们用什么样的方法来求出两个图形的周长呢，今天我们就一起来研究一下长方形和正方形周长的计算方法。(板书:长方形和正方形周长的计算方法) (二) 实践探究，小组讨论 1.先复习长方形和正方形的特点。 2.引导学生探究长方形的计算方法 (1)课件出示长方形，组织活动量一量。 现在我们用先量后算的方法，先来计算这张长方形的长和宽， 再根据量出的长度算出周长。给每名学生都准备长方形的学具， 请学生用学生尺量出长方形的长和宽，再算一算长方形的周长。 (给学生准备的长方形卡片和老师的是一样规格的) 教师巡视，参与学生的探究活动。 (2)组织汇报，交流展示学习成果:你们是用什么方法得到长方 形的周长的,(教师结合学生的回答演示课件。) (3)引导学生对算法进行优化。 to achieve high quality project. 5. instrument installation construction alternatives 5.1 5.1.1 the instrument construction methods General requirements 5.1.1.1 to ensure smooth instrument construction, instrument technician prior to construction workers, have a thorough check, calculate construction materials and technology to give the low-down the construction workers. 5.1.1.2 closely linked to pipeline construction of the instrument unit, with the active cooperation, so as to avoid the instrument device is not properly installed and rework and, if necessary, corresponding with the related technical or construction plan key single equipment prior to commissioning, shall report the test application by party representatives, representatives of the management company and the factory specialists is confirmed, in order to perform. 5.1.1.3 strictly quality inspection system, each process was finished, filled in by the workers, technicians and construction quality inspection requests, advance written notice to the management company site engineer and QC personnel, make conclusions on construction quality in the future, quality form a basis of the project when completed. 5.1.1.4 strictly professional transfer of process quality inspection system, handling written delivery list. The transfer of professional process, must be fully installed quality inspection processes installed on disqualification, shall not be carried out the next working procedure operation; important instrumentation engineering processes must inform the management company engineers check and a written record. 5.1.1.5 strictly abide by the national regulation and construction site safety regulations to ensure 同学们想出了这么多种方法来计算这张长方形卡片的周长，真了 不起～那在这些方法中，你最喜欢哪一种,为什么, 结合学生回答，板书:长方形周长=(长+宽)×2 3.引导学生探究正方形的周长计算方法。 (1)课件出示正方形，组织活动量一量。 现在我们用同样的方法，来计算正方形的周长。动手量正方 形的边长，并计算正方形的周长。 (2)组织汇报，交流展示学习成果。 结合汇报，演示课件。 (3)你更喜欢哪一种方法呢, 板书:正方形周长=边长×4 4. 比较总结。 通过刚才的计算，我们已经知道两个图形的周长了。现在，谁能说说哪个图形所用的绳子的长度更长些, 通过刚才的探究活动，我们知道要求“长方形和正方形的周长”的方法很多，归纳观察这些方法，我们发现要计算长方形的周长，一定要先知道长方形的长和宽的长度;要求正方形的周长只要知道正方形的一条边长就可以了。我们掌握了这两种周长的计算方法之后，就可以解决很多实际问题了。 (三) 巩固知识，综合运用 to achieve high quality project. 5. instrument installation construction alternatives 5.1 5.1.1 the instrument construction methods General requirements 5.1.1.1 to ensure smooth instrument construction, instrument technician prior to construction workers, have a thorough check, calculate construction materials and technology to give the low-down the construction workers. 5.1.1.2 closely linked to pipeline construction of the instrument unit, with the active cooperation, so as to avoid the instrument device is not properly installed and rework and, if necessary, corresponding with the related technical or construction plan key single equipment prior to commissioning, shall report the test application by party representatives, representatives of the management company and the factory specialists is confirmed, in order to perform. 5.1.1.3 strictly quality inspection system, each process was finished, filled in by the workers, technicians and construction quality inspection requests, advance written notice to the management company site engineer and QC personnel, make conclusions on construction quality in the future, quality form a basis of the project when completed. 5.1.1.4 strictly professional transfer of process quality inspection system, handling written delivery list. The transfer of professional process, must be fully installed quality inspection processes installed on disqualification, shall not be carried out the next working procedure operation; important instrumentation engineering processes must inform the management company engineers check and a written record. 5.1.1.5 strictly abide by the national regulation and construction site safety regulations to ensure 今天大家真不简单，经过自己的努力，学会了计算正方形周长方形的周长，既然大家有这么大的本领，那老师有两个问题想请教大家。(ppt显示练习题) 巩固练习: (1)一块长方形的台布，长5分米，宽4分米，在它的四周绣上花边，花边长多少分米, (2)一个正方形的镜框，四周用木条钉成，镜框的边长是5分米，最少需要木条多少分米, (四)总结全课 1.通过今天的学习，你一定会有不少的收获吧～谁来说说和大家分享一下你的收获。 2(老师总结: 小口诀，巧学易记 周长计算并不难，分清图形是关键; 长方形周长很简单，长宽之和再乘2; to achieve high quality project. 5. instrument installation construction alternatives 5.1 5.1.1 the instrument construction methods General requirements 5.1.1.1 to ensure smooth instrument construction, instrument technician prior to construction workers, have a thorough check, calculate construction materials and technology to give the low-down the construction workers. 5.1.1.2 closely linked to pipeline construction of the instrument unit, with the active cooperation, so as to avoid the instrument device is not properly installed and rework and, if necessary, corresponding with the related technical or construction plan key single equipment prior to commissioning, shall report the test application by party representatives, representatives of the management company and the factory specialists is confirmed, in order to perform. 5.1.1.3 strictly quality inspection system, each process was finished, filled in by the workers, technicians and construction quality inspection requests, advance written notice to the management company site engineer and QC personnel, make conclusions on construction quality in the future, quality form a basis of the project when completed. 5.1.1.4 strictly professional transfer of process quality inspection system, handling written delivery list. The transfer of professional process, must be fully installed quality inspection processes installed on disqualification, shall not be carried out the next working procedure operation; important instrumentation engineering processes must inform the management company engineers check and a written record. 5.1.1.5 strictly abide by the national regulation and construction site safety regulations to ensure 正方形周长不算难，边长乘4最简便 (五)布置作业 思考题:求下面图形的周长, 10cm 8cm 6cm 6cm (1) 4cm 10cm 同学们根据今天所学的长方形周长的计算方法，思考一下第二个 图形的周长该怎么样计算，大家回家研究思考一下，我们下节课再来 探讨这个图形周长的计算方法。 六、板书设计 长方形和正方形周长的计算方法 20cm 20cm 10cm 方法:(1)20+10+20+10=60cm (1)20+20+20+20=80cm to achieve high quality project. 5. instrument installation construction alternatives 5.1 5.1.1 the instrument construction methods General requirements 5.1.1.1 to ensure smooth instrument construction, instrument technician prior to construction workers, have a thorough check, calculate construction materials and technology to give the low-down the construction workers. 5.1.1.2 closely linked to pipeline construction of the instrument unit, with the active cooperation, so as to avoid the instrument device is not properly installed and rework and, if necessary, corresponding with the related technical or construction plan key single equipment prior to commissioning, shall report the test application by party representatives, representatives of the management company and the factory specialists is confirmed, in order to perform. 5.1.1.3 strictly quality inspection system, each process was finished, filled in by the workers, technicians and construction quality inspection requests, advance written notice to the management company site engineer and QC personnel, make conclusions on construction quality in the future, quality form a basis of the project when completed. 5.1.1.4 strictly professional transfer of process quality inspection system, handling written delivery list. The transfer of professional process, must be fully installed quality inspection processes installed on disqualification, shall not be carried out the next working procedure operation; important instrumentation engineering processes must inform the management company engineers check and a written record. 5.1.1.5 strictly abide by the national regulation and construction site safety regulations to ensure (2)(20X2)+(10X2)=60cm (2)20X4=80cm (3)(20+10)X2=60cm 总结: 长方形的周长=(长+宽)X2 正方形的周长=边长X4 七、 教学反思 1.在整节课的教学过程中我通过让学生自我探究、小组合作等方式进行教学活动的，想通过学生自主的探讨，提高学生在课堂上的参与度，使学生成为课堂的主体，而教师则是引导者，组织者，不断的激发学生的兴趣，使学生更好的参与到课堂的教学活动中，也培养学生合作的精神，并且让学生获得成功的喜悦。 2.但这节课中还存在许多的不足，内容重复的次数较多，语言有些啰嗦，没能顾及到全班的同学，在今后的教学中我会改进，争取做得更好。也会汲取老师和同学们给我的建议，把教学活动进行的更好，创造出一个学生喜欢的，活泼、丰富多彩的课堂。 to achieve high quality project. 5. instrument installation construction alternatives 5.1 5.1.1 the instrument construction methods General requirements 5.1.1.1 to ensure smooth instrument construction, instrument technician prior to construction workers, have a thorough check, calculate construction materials and technology to give the low-down the construction workers. 5.1.1.2 closely linked to pipeline construction of the instrument unit, with the active cooperation, so as to avoid the instrument device is not properly installed and rework and, if necessary, corresponding with the related technical or construction plan key single equipment prior to commissioning, shall report the test application by party representatives, representatives of the management company and the factory specialists is confirmed, in order to perform. 5.1.1.3 strictly quality inspection system, each process was finished, filled in by the workers, technicians and construction quality inspection requests, advance written notice to the management company site engineer and QC personnel, make conclusions on construction quality in the future, quality form a basis of the project when completed. 5.1.1.4 strictly professional transfer of process quality inspection system, handling written delivery list. The transfer of professional process, must be fully installed quality inspection processes installed on disqualification, shall not be carried out the next working procedure operation; important instrumentation engineering processes must inform the management company engineers check and a written record. 5.1.1.5 strictly abide by the national regulation and construction site safety regulations to ensure to achieve high quality project. 5. instrument installation construction alternatives 5.1 5.1.1 the instrument construction methods General requirements 5.1.1.1 to ensure smooth instrument construction, instrument technician prior to construction workers, have a thorough check, calculate construction materials and technology to give the low-down the construction workers. 5.1.1.2 closely linked to pipeline construction of the instrument unit, with the active cooperation, so as to avoid the instrument device is not properly installed and rework and, if necessary, corresponding with the related technical or construction plan key single equipment prior to commissioning, shall report the test application by party representatives, representatives of the management company and the factory specialists is confirmed, in order to perform. 5.1.1.3 strictly quality inspection system, each process was finished, filled in by the workers, technicians and construction quality inspection requests, advance written notice to the management company site engineer and QC personnel, make conclusions on construction quality in the future, quality form a basis of the project when completed. 5.1.1.4 strictly professional transfer of process quality inspection system, handling written delivery list. The transfer of professional process, must be fully installed quality inspection processes installed on disqualification, shall not be carried out the next working procedure operation; important instrumentation engineering processes must inform the management company engineers check and a written record. 5.1.1.5 strictly abide by the national regulation and construction site safety regulations to ensure