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1、青岛版小学数学四年级下册第一单元教案2009-03-02 13:51:16|分类：教案|举报|字号 订阅总第 1 课时时间：年月日课题用字母表示数课型新授课教学目标在具体情境中理解用字母表示数的意义，初步掌握用字母表示数的方法，教学重点难点在学习中逐步感受符号化思想，发展抽象概括能力。课时分配第 1 课时教法读书指导、讨论法教具教学挂图、教学磁带教学过程一、迁移引入、揭示新课师：你知道我们的母亲河指哪条河吗？你去过黄河三角洲吗？你知道那里有什么好玩地方吗？师：同学们的知识真丰富，数学上也经常用到字母，今天我们就来研究。二、设疑激趣、展开新课1.师生互动，猜年龄；师：你今年几岁了？（板书：的岁数
2、 10 岁）想知道李老师的年龄吗？师：李老师比大25 岁，我今年多少岁了？你是怎么算的？师：当1 岁时，老师该多少岁呢？谁能用式子来表示？个人加减精品w o r d 可编辑资料-第 1 页，共 30 页-当2 岁时，又该用哪个式子来表示？当50 岁时呢？板书：的岁数老师的岁数板书：的岁数老师的岁数10+25 1+25 2+25 50+25 师用手势竖着指，示意引导学生观察：请你仔细观察这里什么在变？（年龄）什么没变？（师明确李老师比大25岁，这个数量关系始终没变。）用字母a 来表示的年龄，那么老师的年龄应该怎么表示？为什么要用a+25表示？师：在这里字母 a 表示什么？（表示的岁数）+25表示
3、什么？含有字母a 的式子 a+25呢？追问：a+25表示的是你们几岁时老师的年龄呢？（生：任一年年龄的时候）a+25 表示的年龄与上面这样一个一个举例子比较有什么好处呢？比较归纳，揭示课题：用含字母的式子可以表示人的年龄、书的本数等等这样的数量。这就是今天这节课我们要研究的用含字母的式子表示数量。三、运用知识，解决问题1.用字母表示数解决第一单元黄河掠影的信息窗一，精品w o r d 可编辑资料-第 2 页，共 30 页-文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX
4、5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X
5、3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX
6、5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X
7、3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX
8、5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X
9、3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX
10、5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2以小组为单位完成（出示情景图）你能提出什么数学问题？师：你能用一个式子简明地表示出任何年份地造地面积吗？教师引导小结：这时候就出现了用字母表示数，通常用t表示时间，t 年地造地面积表示为t 25，可以写作 25t 2.t 年后黄河三角洲的面积约是多少平方千米？引导学生分析：现在的面积（原来的）+新造地的面积（增加的面积）5450+25t 求值：当 t=8 时，黄河三角洲的面积约是多少平方千米？学生试着解答。全班订正。（强调不写单位名称）师：今天我们上了一节与字母有关的数学课，生活中你见到用字母表示过什么吗？（生举例、交流）设计意
11、图 让学生根据数量关系列出造地面积的公式，并解释每一个式子所表示的意义，给学生提供一个创造符号的机会，使学生体验到用符号表示数的必要性，建立字母式子的模型，充分体会用字母表示数的方法、作用和优越性。四、全课完善建构师：通过刚才的学习我们知道用含字母的式子，还可以表示生活中许许多多的数量，那么用含字母的式子表示数量有什么好处？又有什么需要注意的呢？指名生说一说。2、省略乘号，写出下面各式 5 3 b 8 bb 1精品w o r d 可编辑资料-第 3 页，共 30 页-文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3
12、X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码
13、:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3
14、X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码
15、:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3
16、X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码
17、:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3
18、X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A23、课本第 4 页 3、4、5、设计意图 紧密联系学生的生活实际，加以练习，调动学生学习的兴趣，提高练习的实效，学生在掌握基础知识的同时，提出问题，解决问题的能力也得到同步发展。同时让他们再次感受到通过自己的努力换来成功的喜悦，把学生对数学的兴趣延伸了下去。五、灵活运用，拓展延伸学校体育组买了 a 个羽毛球，每个 3 元，买了 20 个排球，每个 b 元。下面式子分别表示什么意思，和小组内的同学相互说一说。3a 20b a-20 20b-3a 3a+20b 设计意图 通过交流让他们再
19、次感受到通过自己的努力换来成功的喜悦，把学生对数学的兴趣延伸了下去。六、课堂小结，自我评价师：这节课我们学了用字母和含有字母的式子表示数。如果让你为自己今天的表现打分，你想给自己打多少分？总第 2 课时时间：年月日课题用字母表示数课型练习教学目标在具体情境中理解用字母表示数的意义，初步掌握用字母表示数的方法，教学重点难点在学习中逐步感受符号化思想，发展抽象概括能力。课时分配第 2 课时教法读书指导、讨论法教具小黑板精品w o r d 可编辑资料-第 4 页，共 30 页-文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2
20、I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档
21、编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2
22、I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档
23、编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2
24、I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档
25、编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2
26、I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2一、创设情境，复习新知。出示黄河边上一个小村庄的图画，村子旁边有一个池塘，课件出示儿歌：一只青蛙一张嘴，两只眼睛四条腿；两只青蛙张嘴，四只眼睛八条腿师生做游戏：儿歌接龙：一只青蛙一张嘴，两只眼睛四条腿；两只青蛙张嘴，四只眼睛八条腿老师问：谁能用我们上节课学过的知识，找出规律，用含有字母的式子表示出来。（a 只青蛙 a张嘴，2a 只眼睛 4a 条腿）二、走进村庄进行巩固练习。谈话：想去这个美丽的村子吗？在去的路上还要先解决一些数学问题，你们有信心吗？1.过河：村子旁的一条大河，大坝
27、高154米，水面到坝顶的高度是x 米。水面以下的大坝高度是（）米。集体分析问题，然后再让学生独立做。个人加减1.过河：村子旁的一条大河，大坝高154米，水面到坝顶的高度是x 米。水面以下的大坝高度是（）米。集体分析问题，然后再让学生独立做。2.参观果园：谈话：刚才我们轻轻松松的过了河，继续往前走吧。（课件出示一个果园）看，你发现了什么？。精品w o r d 可编辑资料-第 5 页，共 30 页-文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V
28、2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文
29、档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V
30、2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文
31、档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V
32、2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文
33、档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V
34、2I3X7X3 ZZ7P6Q8V6A2课件出示第 9 题：一篮香蕉：m千克一篮苹果：n千克你能说出每个式子表示的意思吗？m-n mn 4mm 2n 小组交流，集体订正3.走进学校：（1）学校操场上正在进行一场篮球赛，我们一起来看看吧，出示第 7 题：每投中一个得 2 分。小云投中了 a 个，小华投中了 b 个。小云得了（）分。小华得了（）分。小云比小华多得（）分。让学生独立完成，集体交流。（2）我们再到教室去看看吧，就参观4 年级吧，看，黑板上的题你会做吗？出示第 8 题：磁悬浮列车的速度可达到432 千米/时，进站前，平均每分钟减速 a 千米。6 分钟后，速度减少了（）千米；9分钟后，速度为
35、（）千米。第二问可以先小组内讨论，然后再让学生做。4.穿过树林：师：学校前面出现了一片树林（课件出示第10 题）速生杨的树径每年大约增长3 厘米。精品w o r d 可编辑资料-第 6 页，共 30 页-文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6
36、A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 H
37、B9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6
38、A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 H
39、B9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6
40、A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 H
41、B9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2如果栽种时的树径魏5 厘米，x 年后这棵树的树径是多少厘米？当 x=6 时，这棵树的树径是多少厘米？第二步求式子的值。由于题目的内容离学生的生活较远,学生对
42、题中所说的事情比较陌生。练习时,可先给学生讲清题目说的是什么事情 ,待学生弄明白题意后 ,再进行练习。课件继续显示：速生杨的面积是 100 公顷，松树的面积比速生杨多了x 公顷。当 x=80 时，松树有多少公顷？让学生独立做，集体订正三、评价鼓励，全课总结谈话：这节课，我们参观了黄河边的村庄，解决了有关的问题。每一个同学都开动了脑筋，通过与周围同学的密切合作和自己的主动探索获得了许多知识。谁想说一说在这节课上我们连习了哪些内容？你有什么收获？四、布置作业第 6-7 页 1214 题。总第3 课时时间：年月日课题用字母表示数量关系和计算公式课型新授课教学目标结合具体情境，学会表示常用的数量关系和
43、计算公式。教学重点感受数学语言表达的简洁性，体会数学的价值精品w o r d 可编辑资料-第 7 页，共 30 页-文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档
44、编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2
45、I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档
46、编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2
47、I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档
48、编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2
49、I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2文档编码:CX5L5A7J4V2 HB9V2I3X7X3 ZZ7P6Q8V6A2难点课时分配第 3 课时教法讲解,练习教具小黑板一、创设情境，导入新课。教师谈话：同学们，你们喜欢体育运动吗？那么你们知道漂流是一种怎样的体育项目吗？简单介绍：漂流-漂于水上，顺水流动。漂流，曾是人类一种原始的涉水方式。后来一些喜欢户外活动的人
50、尝试着把退役的充气橡皮艇作为漂流工具，逐渐演变成今天的水上漂流运动。驾着无动力的小舟，利用船桨掌握好方向，在时而湍急时而平缓的水流中顺流而下，在与大自然抗争中演绎精彩的瞬间，这就是漂流，一项勇敢者的运动。（随介绍出示照片）。黄河漂流可不仅是体育项目，它还具有探险性，二、组织探究，解决问题。1.解析情境图观察情境图，你看到了什么？从图上你看到了哪些信息？同学们对情境图观察得真仔细，请继续观察（出示漂流记录表），这是漂流队每天漂流情况记录表，仔细观察：记录表中给出了什么数学信息个人加减2.提出问题根据记录表中的信息，你能提出什么问题？（每天各漂流多少千米？）怎样求每天漂流的路程呢？（漂流路程=漂流