青岛版六年级数学下册教案.doc

a chance to make a trip into space with my friend li yanping, an astronomer. we visited the moon in our spaceship!before we leave, li yanping explained to me that the forece of the gravity would change three times on our journey and that the first change would be the most powerful. then we were off. as the rocket rose into the air, we were pushed back into our seats because we were trying to escape the pull of the earths gravity. it was so hard that we could not say anything to each other. gradually the weight lessened and i was able to talk to him. “ why is the spaceship not falling back to the earth? on the earth if i fall from a tree i will fall to ground.” i asked. “ we are too far from the earth now to feel its pull, “ he explained, “ so we feel as if there is no gravity at all. when we get closer to the moon, we shall feel its gravity pulling us, but it will not be as strong a pull as the earths. “ i cheered up immediately and floated weightlessly around in our spaceship cabin watching the earth become smaller and the moon larger.when we got there, i wanted to explore immediately. “ come on,” i said. “ if you are right, my mass will be less than on the earth because the moon is smaller and i will be able to move more freely. i might even grow taller if i stay here long enough. i shall certainly weigh less!” i laughed and climbed down the steps from the spaceship. but when i tried to step forward, i found i was carried twice as far as on the earth and fell over. “ oh dear,” i cried, “ walking does need a bit of practice now that gravity has changed.” after a while i got the hang of it and we began to enjoy ourselves.leaving the moons gravity was not as painful as leaving the earths. but returning to the earth was very frightening. we watched, amazed as fire broke out on the outside of the spaceship as the earths gravity increased. again we were pushed back hard into our seats as we came back to land. “ that was very exhausting but very exciting too,” i said. “now i know much more about gravity! do you think we could bisit some stars next time?” “of course,” he smiled, “ which star would you like to go to?”caught by a black holethe spaceship warned li yanping and me to be ready as we were approaching the “black hole”. we could see some faint lights around what looked like an empty space. li yanping said, “ that empty hole is like a mouth always needing to be fed. those lights are thins that are being pulled into time by the gravity of the hole.” we watched with interest and amazement at the lights which seemed to be going fainter and fainter round the edge of the black hole. just then the lights on our spaceship went our the and the computer stopped working. what was happening? i tried to turn the spaceship away from the hole but it would not move. would it eat us too?suddenly the spaceship jumped and began to move round the edge of trhe hole too. the gravity of the “black hole” was pulling us into its “mouth”. as the spaceship moved round the black hole, i felt rather sick. my mouth went dry and i closed my eyes. all the stories about what happened when you were caught by the gravity of a “black hole” seem to be true.but then the spaceship jumped again. this time it moved sideways and away from this edge of the “black hole”. someone watching me would have seen the spaceship flying like a bird away from the “black hole”. but we felt nothing. at last we were able to look around us. luckily the computer had started working again. we realized that we had discovered something new about “black hole”. if you go inside the edge of a “black hole”, it will “eat” you and there is no escape; but if you do not, you may have an opportunity to escape. how exciting!unit 5a trip on “ the true north”li daiyu and her cousin liu qian were on a trip to canada to bisit their cousins in montreal on the atlantic coast. rather than take the aeroplane all the way, they decided to fly to vancouver and then take the train west to east across canada. the though that they could cross the whole continent was exciting.their friend, danny lin, was waiting at the airport. he was going to take them and their baggage to catch “the true north”, the cross canada train. on the way to the statiion, he chatted about their trip. “youre going to see some great scenery. going eastward, youll pass mountains and thousands of lakes and forests, as well as wide rivers and large cities. some people have the idea that you can cross canda in less than fice days, but they forget the fact that canada is 5500 kilometers from coast to coast. here in vancouver, youre in canadas warmest part. people say it is canadas most beautiful city, surrounded by mountains and the pacific ocean. skiing in the rocky mountains and sailing in the harbour make vancouver one of canadas most popular cities to live in. its population is increasing rapidly. the coast north of vancouver has some of the oldest and most beautiful forests in the world. it is so wet there that the trees are extremely tall, some measuring over 90 metres.”that afternoon aboard the train, the cousins settled down in their seats. earlier that day, when they crossed the rocky mountains, they managed to catch sight of some mountain goats and even a grizzly bear and an eagle. their next stop was calgary, which is famous for the calgary stampede. cowboys from all over the world come to compete in the stampede. many of them have a gift for riding wild horses and can win thousands of dollars in prizes.after two days travel, the girls began to realize that canada is quite empty. at school, they had learned that most canadians live within a few hundred kilometres of the usa border, and canadas population is only slightly over thirty million, but now they were amazed to see such an empty country. they went through a wheat-growing province and saw farms that covered thousands of acres. afrer dinner, they were back in an urban area, the busy port city of thunder bay at the top of the great lakes. because of the great lakes, they learned, canada has more fresh water than any other country in the world. in fact, it has one-third of the worlds total fresh water, and much of it is in the great lakes.that night as they slept, the train rushed across the top of lake superior, through the great forests and southward towads toronto.“the true north” from toronto to montrealthe next morning the bushes and maple trees outside their window were red, gold and orange, and there was frost on the ground, confirming that fall had arrived in canada.around noon they arrived in toronto, the biggest and most wealthy city in canada. they were not leaving for montreal until later, so they went on a tour of the city. they went up the tall cn tower and looked across the lake. in the distance, they could see the misty cloud that rose from the great niagara falls, which is on the south side of the lake. the water flows into the niagara river and over the falls on its way to the sea.they saw the covered stadium, home of several famous basketball teams. as they walked north from the harbour area, li daiyu said, “lin fang, one of my mothers old schoolmates, lives here. i should phone her from a telephone booth.”they met lin fei around dusk in downtown chinatown, one of the three in toronto. over dinner at a restaurant called the pink pearl, the cousins chatted with lin fei, who had moved to canada many years earlier. “we can get good cantonese food here,” lin feitold them, “ because most of the chinese people here come from south china, especially hong kong. its too bad you cant go as far as ottawa, canadas capital. its approximately four hundred kilometers northeast of toronto, so it would take too long.”the train left late that night and arrived in montreal at dawn the next morning. at the station, people everywhere were speaking french. there were sighs and ads in french, but some of them had english words in smaller letters. “we dont leave until this evening,” said liu qian. “lets go downtown. old montreal is close to the water.” they spent the afternoon in lovely shops and visiting artists in their workplaces beside the water. as they sat in a buffet restaurant looking over the broad st lawrence river, a young man sat down with them.“hello, my name is henri. im a student at the university nearby,” he said,” and i was wondering where you are from.” the girls told him they were on a trp across canada and that they had only on day in montreal. “thats too bad,” he said. “montreal is a city with wonderful restaurants and clubs. most of us speak both english and french, but the city has french culture and traditions. we love good coffee, good bread and good music.”that night as the transfer was speeding along the st lawrence river toward the gulf of st lawrence and down to the distant east coast, the cousins dreamed of french restaurants and red maple leaves.iqaluit the frozen townthe reporter, beth allen, arrived in a northern community called iqaluit in nunavut. nunavut was created in 1999 as a special area for inuit people. its name means “our land” in their language. it is in the farthest northeastern area of canada, north or the arctic circle, and is very cold the average witer temperature in nunavut is 35 degrees below zero.beth said, “ i knew it would be could in january, but not this cold! maybe there is a dog sled that can take me into town.”the quiet man who had been on the plane with her said, “ill take you into town, but i dont hace a dog sled. most people only use the dogs for competitions, why are you visiting iqaluit?”beth answered, “ im writing a story for my newspaper about iqaluit wed like to advertise it as a holiday place, but i think its too cold.”the man laughed. “my name is simon and i am inuit,” he said. “i think its too far north here for holidays but more and more tourists are coming. they like ice fishing and photographing polar bears. i star as far away from polar bears as possible. i like my warm office and my warm house.”“im business man. my grandfather would live in ice houses when he hunted in winter, but not so many people do that now. the old men used to make one in a few hours. they used to live in skin tents in summer the tents were easy to move so the people could follow the animals.”a few minutes later they arrived in iqaluit, a town with a population of 6000, on simons snowmobile. it was two oclock in the afternoon, but it was already dark, and all the houses shone with bright lights. beth said, “ why is it so dark? its the middle of the day!”simon replied, “its dark in the day because we are so far north. you should come in june. the sun shines all night in the north then.青岛版六年级数学下册备课主备人：王延京横里路小学青岛版六年级下册第一单元信息窗一 信息窗一：求一个数比另一个数多（或少）百分之几教学内容：义务教育课程标准实验教科书青岛版小学数学十二册第一单元信息窗一：求一个数比另一个数多（少）百分之几；成数的意义及简单应用。教材简析：该信息窗呈现的是济南市10月2日客运情况的统计表。统计表提供了2003年和2004年的10月2日济南市民航、铁路、公路运输游客量的比较情况。通过解决“2004年民航的客运量比2003年同期增长百分之几”和“10月3日去济南近郊旅游的人数比10月2日减少百分之几”等问题，引入对“求一个数比另一个数多（少）百分之几”知识的学习。教学目标：1使学生初步掌握“求一个数比另一个数多（或少）百分之几”的实际问题的分析方法，并能正确解答此类生活中的实际问题。2进一步提高分析、比较、解答实际问题的能力，培养学生认真审题的好习惯。教学重难点：掌握“求一个数比另一个数多（或少）百分之几”的实际问题的分析方法，并能够正确列式解答。预习案1、说出下面各题中是哪两个量相比，把谁看作单位“1”？（1）女生人数占总人数的百分之几？（2）故事书的本数相当于科技书本数的百分之几？（3）今年产量是去年产量的百分之几？（4）苹果的棵数是梨的百分之几？2、说出下面两个数的相差量。（1）三（1）班有44人，三（2）班有49人。三（1）班比三（2）班少（ ）人，三（2）班比三（1）班多（ ）人，两个班相差（ ）人。（2）甲数是100，乙数是80，甲和乙的相差数是（ ）。（3）实际比计划多生产了200吨，实际和计划的相差量是（ ）吨。导学案教学过程：第1课时一、创设情境、激趣导入：谈话：同学们，十一黄金周期间，人们往往选择外出游玩，下面我们一起来看看济南市客运情况。二、自主探究、获取新知：1提出问题，明确目标：谈话：观察统计图，你获得了哪些信息？你能提出什么数学问题？教师根据学生的提问，有选择的进行板书，如：2004年民航的客运量比2003年同期增长百分之几？让学生独立完成：（1）请自己试着画线段图分析（2）独立思考，同桌讨论，解决问题。学生汇报交流，引导学生得出：2004年民航的客运量比2003年增长百分之几，就是指2004年比2003年增长的人数是2003年的百分之几。我们可以先算2004年的客运量比2003同期多多少万人，再算2004年比2003年增长的数量是2003年的百分之几。列式：（0.490.47）0.47 0.020.47 0.043 4.3%答：2004年民航的客运量比2003年同期增长4.3%。（3）谈话：我们在计算时，如果除不尽需要保留三位小数，然后再化成百分数。这道题还有其它解法吗？ （4）学生独立思考，小组讨论，集体交流。（交流时结合线段图分析）列式：0.490.4711.04310.0434.3% 答：2004年民航的客运量比2003年同期增长4.3%。（5）让学生分析自己的解答思路，引导学生得出：先算2004年的客运量是2003年的百分之几，然后再算2004年民航的客运量比2003年同期增长百分之几？提问：这儿为什么要减去1？引导学生回答得出：0.490.47求的是2004年的客运量是2003年的百分之几，而题目要求2004年比2003的多百分之几，我们把2003年客运量看作“1”，所以要减去1。2合作交流，自主探究出求绿点例题：10月2日去济南近郊旅游的人数约为1万人，10月3日约为0.8万人。10月3日比10月2日减少百分之几？（1）谈话：“10月3日比10月2日减少百分之几？”是哪两个量在比较？我们把哪个量看作“1”？（预设）（2）学生交流汇报：我们把10月2日的旅游人数看作单位“1”。10月3日比10月2日减少百分之几？就是指10月3日比10月2日减少的数量相当于10月2日的百分之几。（3）请根据你自己的理解列出算式（4）展示学生算式：（预设）方法1：（10.8）1 方法2： 10.810.21 10.820% 0.220%答：10月3日比10月2日减少20%。 答：10月3日比10月2日减少20%。 （5）让学生说说自己列式的依据。 小结：刚才我们学习了如何解答一个数比另一个数多（或少）百分之几类型的题目上，你觉得解答这类应用题的关键是什么？（找准把谁看作单位“1”，谁和谁比较）随机练习：（1）4是5的（ ）% 5是4的（ ）%（2）5比4多（ ）% 4比5少（ ）%三、巩固练习1说说下面各句分别把谁看作单位“1”，谁和单位“1”比较？（1）五（1）班做的好事比五（2）班多百分之几？（2）今年产量超额百分之几？2（自主练习1）文化路小学五年级有男生100人，女生125人。（1）男生人数比女生少百分之几？（2）女生人数比男生多百分之几？本题是 “求一个数比另一个数多（少）百分之几”问题的基本练习。在学生独立解答的基础上，引导学生进行分析比较：因为“男生比女生少百分之几”是把女生人数看作单位“1”，而“女生比男生多百分之几”是把男生人数看作单位“1”，所以男生比女生少百分之几与女生比男生多百分之几结果不相同。3只列式不计算（1）某校有男生500人，女生450人，男生比女生多百分之几？（2）某工厂计划制造拖拉机550台，比原计划超额完成了50台，超额了百分之几？4自主练习第2题、第3题：出示题目，引导学生分析关系，然后再独立完成，集体交流。5判断：甲比乙多10%，乙比甲少10% （ ）讨论：为什么甲比乙多10%，而乙比甲不是少10%呢？难道我们做错了吗？学生比较寻找相同点和不同点；学生之间讨论，明白“1”的变化引起的变化四、课堂小结：这节课我们研究了什么问题？你有什么收获？（引导学生进行总结，能用自己的话说出学习主要内容。）课外拓展学案1、根据问题列出算式，不计算。超市有大米50袋，面粉40袋。大米袋数是面粉的百分之几？列式：（ ） 面粉是大米的百分之几？列式：（ ） 大米比面粉多百分之几？列式：（ ） 面粉比大米少百分之几？列式：（ ） 2、小飞家原来每月用水约10吨，更换了节水龙头后每月用水约9吨，每月用水比原来节约了百分之几？（注意“节约”的意思）3、为了缓解交通拥挤的状况，某市正在进行道路拓宽。团结路的路宽由原来的12米增加到25米，拓宽了百分之几？（注意“拓宽”的意思）教学反思：个别学生辅导：第2课时预习学案1、东山村去年原计划造林16公顷，实际造林20公顷。实际造林比原计划多百分之几？引导思考： 这个问题是把哪两个数量进行比较？比较时以哪个数量作为单位1？要求实际造林比原计划多百分之几，就是求哪个数量是哪个数量的百分之几？2、思考：还可以怎样计算？3、 出示：东山村去年原计划造林16公顷，实际造林20公顷。原计划造林比实际少百分之几？思考：要求原计划造林比实际少百分之几，就是求哪个数量是哪个数量的百分之几？导学案一、创情导入同学们，上节课我们学习了如何解答一个数比另一个数多（少）百分之几的题目，这节课我们来运用学到的解题方法，去解决求一个数比另一个数多（或少）百分之几的实际题目。老师相信，同学们一定能够凭借自己的努力解决好每个问题的。 设计意图教师运用鼓励性的语言，使学生明确本节课学习目标，激发调动学生参与学习探究的兴趣和欲望，有效提高课堂效率。二、运用知识，解决问题1出示题目：一个乡去年原计划造林12公顷，实际造林14公顷，实际比计划多造林百分之几？学生自主解答，集体交流。（交流时让学生说说解题的思路）把问题改为“计划比实际少造林百分之几？”怎么求？思考：两道题有什么相同的的地方？有什么不同的地方？2自主练习第5题李叔叔家近两年三种果品产量情况如下。 品种产量kg时间核桃板栗冬枣去年150400200今年120460250（1）今年核桃的产量比去年减少几成？（2）今年板栗的产量比去年增加了几成？（3）你还能提出什么问题？设计意图引导学生学习有关“成数”的知识。可以结合教材中的注释向学生讲清“成数”的实际意义及其作用，然后放手让学生独立解决。通过讨论、交流让学生明确，解题思路是一样的，只是要把最后的结果化成成数。随机练习：自主练习第6题。三、巩固练习1分析下面每个题的含义（1）今年的产量比去年的产量增加了百分之几？（2）实际用电比计划节约了百分之几？（3）十月份的利润比九月份的利润超过了百分之几？（4）1999年的电视机价格比1998年降低了百分之几？2对比练习：王爷爷家养了60只公羊，75只母羊（1）公羊只数比母羊只数少百分之几？（2）母羊只数比公羊只数多百分之几？设疑：都是求相差只数的对应分率，为什么母羊比公羊多25%，而公羊比母羊少20%呢？3选择合适的答案把序号填在括号里。光明小学最近装修了一间多媒体教室（1）原计划投资5万元，实际投资只用4万元，节约投资百分之几？ （ ）（2）原计划投资5万元，实际投资节约1万元，节约投资百分之几？（ ）（3）实际投资4万元，比原计划节约1万元，节约投资百分之几？ （ ）a 1（4+1） b（54）5 c 45 d 154自主练习第7题。四、课堂小结通过今天的学习，你有哪些收获？课外拓展学案1甲数是40，乙数是50，甲是乙的（ ）%，甲比乙少（ ）%。 2a是b的125%，a比b多（ ）%，b是a的（ ）%，b比a少（ ）%。 3列式计算 （1）某校有男生500人，女生450人，男生比女生多百分之几？ （2）某校有男生500人，女生450人，女生比男生少百分之几？ （3）一种机器零件，成本从2.4元降低到0.8元，成本降低了百分之几？ （4）一种机器零件，成本从2.4元降低了0.8元，成本降低了百分之几？ （5）某工厂计划制造拖拉机550台，比原计划超额完成了50台，超额了百分之几？ 教学反思：个别学生辅导：信息窗2：青岛假日游百分数实际问题教学内容：义务教育课程标准实验教科书青岛版小学数学十二册第一单元信息窗二。教材简析：该信息窗以青岛市的几个著名旅游景点为背景，提供了2003年和2004年“十一”黄金周期间来青岛的游客人数和旅游收入等信息，通过解决“到海滨风景区的游客大约有多少万人”、“2004年十一黄金周青岛旅游收入约多少亿元”和“2003年同期到青岛旅游的约有多少万人”等问题，引入对“求一个数的百分之几是多少”、“求比一个数多（少）百分之几的数是多少”和“已知比一个数多（少）百分之几的数是多少，求这个数”等知识的学习。这部分知识是本单元的教学难点。教师要充分重视知识的迁移性，充分利用学生已有的知识来学习。由分数问题的解决方法迁移到这一类百分数问题的解决方法。教学目标：1通过学习使学生掌握百分数应用题的数量关系，能够正确解答“求一个数的百分之几是多少的应用题。”2培养学生分析、解答应用题的能力。3通过学习活动，培养积极的学习态度，树立学好数学的信心。预习案画图分析并列式，不计算:1、一堆煤重2500吨，用去2/5，用去了多少吨？2、学校图书室原有图书1400册，今年图书册数增加了2/7，现在图书室有多少册图书？导学案教学过程：第1课时一、创设情境、激趣导入：谈话：同学们，青岛作为国家著名的旅游胜地，气候怡人，景色优美，每年“十一”期间都会迎来大量游客到青岛旅游，我们能生活在这样一座美丽的海滨城市非常的幸福。设计意图 从学生感兴趣的话题引入，让学生谈一谈自己对青岛的印象，具体到海滨风景区有什么印象，旅游时的感受等，然后引导学生看数学信息，提出问题。二、自主探究、获取新知：1、仔细观察情境图，收集题中的数学信息，提出问题谈话：观察情境图，你获得了哪些信息？你能提出什么数学问题？预设：（1）到海滨风景区的游客大约有多少万人？（2）到其他景区的游客大约有多少万人？教师根据学生的提问，有选择的进行板书，如：到海滨风景区的游客大约有多少万人？（学生提出的其他合理问题先放进问题口袋，下节课再解决）下面我们先来解决“到海滨风景区的游客大约有多少万人？”课件出示第一个红点例题。引导学生分析数量关系。（1）读题。找条件和问题，明确这道题是把谁看成单位“1”。设计意图 审题是正确解题的前提。学生往往对审题拘于形式，拿到题目就把题中数字简单组合，导致错误。（2）学生画图并自己试做。设计意图充分发挥线段图的直观教学作用。线段具有一定的直观性，能够化抽象为具体，有效地揭露题目中的数量关系，从而理清并掌握数量关系。谈话：要求到海滨风景区的游客大约有多少万人？该怎样计算呢？你能不能联系前面我们学过的求一个数的几分之几的解答方法，先自己想一想该如何列式，并说说列式的依据。列好算式后，请学生独立计算，最后再交流计算结果。102 84% 1020.84=85.68（万人）答：到海滨风景区的游客有85.68万人。谈话：我们在列式时为什么要用乘法计算？学生同桌讨论后让学生交流自己的观点。引导学生得出：我们把黄金周到青岛旅游的总人数看作单位“1”， 已知到海滨风景区的占总人数的84%，要求到海滨风景区的人数，就是求102万人的84%是多少。所以用乘法。补充练习：（1）张红看一本200页的书，已经看了全书的80%，看了多少页？（2）工人叔叔要加工1500个零件，还剩下10%没有加工完，还剩下多少个没有加工完？（学生自主完成，集体交流）设计意图通过补充练习，帮助学生进一步巩固解决“求一个数的百分之几是多少”这类问题的思路和方法。2课件出示自主练习第7题敦煌莫高窟藏经洞出土文献5万余件。这些珍贵的文献约有70%流失海外，国内现存莫高窟出土文献约有多少万件？（1）画图，理解题意（2）小组交流，列出算式后汇报：方法（1）：5570% 方法（2）：5（170%）（3）学生四人小组内进行交流，交流解答方法的列式依据。学生可能有的答案是：1.根据线段图我们可以看出要求国内现存莫高窟出土文献约有多少万件？可以先求出流失海外的大约有多少万件，然后再用一共出土的减去流失海外的数量。2.我们小组是根据“这些珍贵的文献约有70%流失海外”这句话先求出了国内现存莫高窟出土文献约占出土文献总量的30%，这时要示国内现存莫高窟出土文献约有多少万件？就是求5万件的30%是多少。随机练习：（自主练习第2题）学生自主解答，集体交流。三、巩固练习1.只列式不计算（1）六年级一班有学生45人，上学期期末跳远测验有80%的同学及格，及格的同学有多少人？（2）油菜子的出油率是42%，2100千克油菜子可以榨油多少千克？2.自主练习第1题：将下面百分数分别化成分数和小数。（学生汇报时说出转化的方法）学生讨论：首先应该做什么？怎么才能提高正确率？自主练习第9题。第12题：在学生独立思考的基础上组织交流，使学生明确该题有两种解题思路：一是先分别求第一期和第二期修的米数，再求第一期比第二期多修的米数；二是先求第一期比第二期多修了全长的百分之几，再求多修的米数。这里不要求学生两种解题方法都掌握。答