六年级数学下册总复习教案.doc

yunnan province near the lancang river, the chinese part of the river that is called the mekong river in other countries. wang wei soon got them interested in cycling too. after graduating from college.we finally got the chance to take a bike trip. i asked my sister, where are we going? it was my sister who first had the idea to cycle along the entire mekong river from where it begins to where it ends. now she is planning our schedule for the trip. i am fond of my sister but she has one serious shortcoming. she can be really stubborn. although she didnt know the best way of getting to places, she insisted that she organize the trip properly. now, i know that the proper way is always her way. i kept asking her, when are we leaving and when are we coming back? i asked her whether she had looked at a map yet. of course, she hadnt; my sister doesnt care about details. so i told her that the source of the mekong is in qinghai province. she gave me a determined lookthe kind that said she would not change her mind. when i told her that our journey would begin at an altitude of more than 5,000 metres, she seemed to be excited about it. when i told her the air would be hard to breathe and it would be very cold, she said it would be an interesting experience. i know my sister well. once she has made up her mind, nothing can change it. finally, i had to give in. several months before our trip,wang wei and i went to the library. we found a large atlas with good maps that showed details of world geography. from the atlas we could see that the mekong river begins in a glacier on a tibetan mountain. at first the river is small and the water is clear and cold. then it begins to move quickly. it becomes rapids as it passes through deep valleys, travelling across western yunnan province. sometimes the river becomes a waterfall and enters wide valleys. we were both surprised to learn that half of the river is in china. after it leaves china and the high altitude,the mekong becomes wide，brown and warm. as it enters southeast asia, its pace slows. it makes wide bends or meanders through low valleys to the plains where rice grows. at last, the river delta enters the south china sea.part2 a night in the mountainsalthough it was autumn,the snow was already beginning to fall in tibet.our legs were so heavy and cold that they felt like blocks of ice.have you ever seen snowmen ride bicycles?thats what we looked like! along the way children dressed in long wool coats stopped to look at us.in the late afternoon we found it was so cold that our water bottles froze.however,the lakes shonelike glass in the setting sun and looked wonderful.wangwei rode in front of me as usual.she is very reliable and i knew i didnt need to encourage her. to climb the mountains was hard work but as we looked around us, we were surprised by the view. we seemed to be able to see for miles. at one point we were so high that we found ourselves cycling through clouds. then we began going down the hills. it was great fun especially as it gradually became much warmer. in the valleys colourful butterflies flew around us and we saw many yaks and sheep eating green grass. at this point we had to change our caps, coats,gloves and trousers for t-shirts and shorts. in the early evening we always stop to make camp.we put up our tent and then we eat. after supper wang wei put her head down on her pillow and went to sleep but i stayed awake. at midnight the sky became clearer and the stars grew brighter. it was so quiet. there was almost no windonly the flames of our fire for company. as i lay beneath the stars i thought about how far we had already travelled. we will reach dali in yunnan province soon, where our cousins dao wei and yu hang will join us. we can hardly wait to see them!part 6 the end of our jouneycambodia was in many ways similar to laos, although it has twice the population. at another inn, we talked with a teacher who told us that half of the people in her country couldnt read or write. her village couldnt even afford to build a school, so she had to teach outside under a large tent. when we said goodbye, we all felt very lucky to have studied in college.back on the road, we passed between many hills and forests. then we came to the plains and entered phnom penh,the capital of cambodia. in many ways it looked like vientiane and ho chi minh city; it also had wide streets with trees in rows and old french houses.unlike vientiane, ships could travel the mekong river here.in the center of the city we visited the palace and a beautiful white elephant. it can only be seen outside the palace on special days. we ate an early supper and went to see a great temple with floors made of sliver.the next morning our group slept late. we were very tired from the long bike ride the day before. cycling in the hills had been diffcuilt.now our couins had the chance to make jokes about wangwei and me. perhaps,they said,they were the strong ones!we had lunch at a nice outdoor cafe,then rode out of the city.two days later we crossed the border into vietnam. we began to see many more people,but i wasnt surprised .i read in an atlas before our trip that vietnam has almost seven times the population of cambodia. we met a farmer who gave us directions and told us that he grows a new rice crop four times every year so he can feed more people.he also told us that the northern part of his country has many mountains and it is much cooler than here in the south,where it is flat.although the flat delta made it easier for us to cycle.we got warm very quickly.so we drank lots of water and ate lots of bananas.soon the delta separated into nine smaller rivers.two days later,after we had passed thousands of rice fields,we came to the sea. we were tired but also in high spirits:our dream to cycle along the mekong river had finally come true.unit 4a night the earth didt sleep strange things were happening in the countriside of northest hebei.for there days the water in the village wells rose and fell, rose and fell.farmers noticed that the well walls had deep cracks in them. a smelly gas came out of the cracks. in the farmeryards,the chickens and even the pigs were too nervous to eat.mice ran out of the fields looking for places to hide.fish jumped out of their bowls and ponds.at about 3:00am on july 28,1976,some people saw bright lights in the sky.the sound of the planes could be heard outside the city,who thought little of these events,were asleep as usual that night. at3:42 am everything began to shake.it seemed as if the world was at an end!eleven kilometres directly below the city the greast earthquake of 20th century had begun. it was felt in beijing,which is more thantwo hundred kilometres away. one-third of the nation felt it .a huge crack that was eight kilometres long and thirty metres wide cut across houses,roads and canals.steam burst from holes in the ground. hard hills of rock became rivers of dirt. in fifteen terrible seconds a large lay in ruins.the suffering of the people was extreme. tow-thirds of them died or were injured during the earthquake.thounds of families were killed and many chidren were left without parents. the number of people who were killed or injured reached more than 400,000.but how could the survivors believe it was natural?everywhere they looked nearly everything was destroyed. all of the citys hospitals,75%of its factories and buildings and 90%of its homes were gone. bricks covered the ground like red autumn leaves. no wind, however,could below they away. two dams and most of the bridges also fell or were not safe for travelling. the railway tracks were now useless pieces of steel. tens of thousands of cows would never give milk again. half a million pigs and millions of chickens were dead. sand now filled the wells instead of water. people were shocked. then later that afternoon,another big quake which was almost as strong as the first one shook tangshan. some of the rescue workers and doctors were trapped under the ruins. more buildings fell down. water,food, and eletricity were hard to get. people began to wongder how long the disater would last. all hope was not lost. soon after the quakes, the army sent 150,000 soliders to tangshan to help the rescue workers. hundreds of thousands of people were helped. the army organized teams to dig out those were trapped and to bury the dead. to the north of the city, most of the 10,000 miners were rescued from the coal mines there. workers built shelters for survivors whose homes had been destroyed. fresh water was taken to the city by train,truck and plane. slowly, the city began to breathe again. a safe home it is sad but that people die in earthquakes from falling furniture and bricks. earthquake safety is very important and there is more to it than just keeping buildings from falling down. so if your home is in an earthquake area,you should prepare carefully before the earthquake comes. first, make sure you buy a house which is earthquake safe. all pipes should be fixed to the wall and all walls should be especially thick and strong. you also have to make sure that there are bolts underneath your house. they are one of the most important ways of protecting a house. make sure the building has no breaken windows and is well repaired. second ,look at the objects in your house. those in the living room,which are the most likely to hurt us, are computers, televisions and lamps. they can be tied to tables or them so they wont easily move around. the kitchen, which is also very dangerous, must have strong doors on all the cupboards. this is the place where many small things are stored that might fall down. the water heater should have a case round it too. windows are special problem. when they break, glass can cause many accidents,. it is better to use safety glass if you can, especially for pictures. always remember:” it is better to be safe than sorry.” the story of an eyewitnessby jack london never before in history has a city been so completely destroyed. san francisco is gone. nothing is left of it but memories and some houses far from the centre of the city. its buniness are gone. the factories,hotelsand palace are all gone too. within an hour after the earthquake, the smoke of sanfrancios fires could been seen 160 kilometres away. the sun is red in the dark sky. there was no stopping the fires. there was no way to organize or communicate. the steel railway tracks were now useless. and the great pipes for carrying water under the streets had burst. all of the ways man had made阳谷县实验小学数学教案课题数的认识（1）序号52教学目标1.比较系统地理解自然数、整数、分数、小数、百分数的意义。2.自然数、整数、分数、小数、百分数的联系和区别。3.对各种数进行分类整理，体验分类整理的原则与方法。教学重点加深对各种数的意义的理解。探究过程教师活动学生活动一、谈话导入同学们，在小学阶段，我们认识了很多的数，你能说说我们学过了哪些数？举例说明(整数、小数、分数、百分数和负整数)二、唤醒记忆，分类整理。01.710312-1-20.310 17771771.用数表示数轴上的各点，唤醒学生对数的认识。（1）教师先确定“0”的位置，然后由学生分别指出1、2、-1、-2所在的点各用什么数表示。（2）引导学生发现规律。从这条线上，你能发现什么规律？学生交流。学生回答。教师活动学生活动探究过程（3）指出、0.3、2.9所在的点各用什么数表示。说说为什么这些点要用分数或小数表示？你还发现了什么？2.回顾整数的意义。 追问：-1、-2是整数吗？3.回顾分数的意义。（1）想用分数表示的例子？（2）谁来说说分数的意义？你对单位“1”是怎样理解的？（3）什么是分数的基本性质？应用分数的基本性质可以解决哪些问题。4.回顾小数的意义。（1）举例什么样的数是小数？你认为小数与分数有怎样的关系？（2）小数的性质是什么？（3）排出小数的数位顺序表，每个数位上的计数单位各是多少？相邻学生交流。学生交流。学生交流。学生回顾交流。学生交流。学生交流。学生交流。学生交流。教师活动学生活动探究过程两个计数单位之间的进率是多少？5.回顾百分数的意义。（1）想用百分数表示信息的例子（2）分数与百分数之间有什么联系和区别？6.（1）复习分数之间的改写和分数、小数、百分数之间的互化。（2）在括号里填上合适的数。2 :（ ）=0.4 = = =（ ）%一个数由7个 组成，这个数是（ ），它的倒数是（ ）。把4千克葡萄干平均分成8包，每包是（ ）千克，每包占总数的（ ）。的分数单位是（ ），再加上（ ）个这样的单位是最小的合数。1（）=0.25=（）%=5：（） -1、0 、1.5、-2.3从小到大排列为（ ）总结 ：你对数又有了哪些新的认识？学生交流。学生举例说明独立完成，集体交流学生交流。板书设计教学反思阳谷县实验小学数学教案 课题数的读写整理和复习序号53教学 目标1.让学生在练习中复习多位数的读、写方法，提高正确读、写多位数的能力。2.能把一个较大数改写成用“万”或“亿”作单位的数的方法，能根据要求用“四舍五入”法省略“万”或“亿”后面的尾数以及求一个数的近似数的方法。3.掌握比较数的大小的方法，培养学生解决实际问题的能力。教学 重点提高正确读、写多位数的能力。 探 究 过 程教师活动学生活动一、复习数的读法、写法（1）数位顺序表。整数部分小数点小数部分亿级万级个级数位个位十分位计数单位个十分之一填一填，读一读。什么是数位？数位与位数相同吗？什么是计数单位？相邻的计数单位之间的进率是多少？ 学生回顾，交流。学生交流。学生交流。教师活动学生活动探究过程（2）读法和写法。读出下面各数。106000000 0.006 25.08、读一读。、说一说读数的方法、要点。写出下面各数。九十万三千 二十亿五千零十八 零点二零零八写一写说一说你是怎么做的。（3）改写。把540000改写成以“万”作单位的数。把24940000000改写成以“亿”作单位的近似数。学生改写。说说改写的方法要点3、数的大小:怎样比较两个数的大小？三、综合练习。1.一个数的亿位上是9，千万位上是5，十万位上是8，千位上是4，其余各位上都是0，这个数写作（ ），读作( ),把它写成用“万”作单位的数是（），把它四舍学生交流。学生交流。学生独立改写，集体交流。学生交流。学生独立填空，集体交流.教师活动学生活动 探究过程五入到亿位是（ ）。2.9个亿和900个万组成的数是（ ），改写成用“亿”作单位的数是（ ），省略“亿”位后面的尾数是（）。3.一个数十万位上是最大的一位数，千位上是最小的合数，个位上是最小的质数，其他数位上都是0，这个数写作?4.15040800.56里面有（）个千万，（）个万，（）个百，（）个十分之一，（）个百分之一。5.一个数的千万位、万位、百位、和百分位上都是2，其它各位上都是0，这个数是（ ）。6.用数字0、7、3、9、8、5组成一个最大的六位数是（ ），最小的六位数是（ ）。7.8.954保留整数是（ ），保留一位小数是（ ），保留两位小数是（ ），改写成百分数是（ ）%。总结：本节课中你有什么收获？学生独立填空，集体交流。学生独立填写，集体交流。学生独立填写，集体交流。学生独立填写，集体交流。学生独立填写，集体交流。学生交流。板书设计数的读写整理和复习整数部分小数点小数部分亿级万级个级数位千亿位百亿位十亿位亿位千万位百万位十万位万位千位百位十位个位.十分位百分位千分位计数单位千亿百亿十亿亿千万百万十万万千百十一个十分之一百分之一千分之一教学反思阳谷县实验小学数学教案课题因数和倍数整理和复习序号54教学目标1.通过回忆和整理进一步明确奇数和偶数、质数与合数、公因数与公倍数的联系与区别 。2.使学生进一步加深对分数的基本性质以及分数与小数、百分数的互化的认识。教学重点探究过程教师活动学生活动一、复习有关倍数和因数的知识1.倍数与因数。（1）什么是倍数、因数？20的因数还有哪些？一共有多少个？4的倍数还有哪些？一共有几个？着重说明：最小最大个数因数1本身有限倍数本身/无限（2）2、3、5倍数的特征。2的倍数特征是什么？举例说明。什么是偶数？什么是奇数？学生举例说明。学生交流。学生交流。学生交流。教师活动学生活动探究过程5的倍数特征是什么？举例说明。3的倍数特征是什么？举例说明。（3）什么是质数？什么是合数？什么是质数？最小的质数是几？什么是合数？最小的合数是几？2.公因数与公倍数（1）写出18和24所有的公因数，并指出其中的最大公因数。（2）从小到大写出4和6的三个公倍数，指出其中最小的公倍数。三、综合练习。填空：1. 9和6的最小公倍数是（ ），最大公约数是（ ）。12和30的最大公因数是（ ），最小公倍数是（ ）。2.如果=c（a、b、c都是不等于0的自然数），a和b的最大公约数是（），最小公倍数是（ ）3.如果把的分子加上21，要使分数的大小不变，分母应加上（ ）。4. 把48分解质因数是（ ）学生交流。学生交流。学生交流学生交流。学生交流。学生独立填空，集体交流。教师活动学生活动探究过程5.a=223,b=233,a和b的最大公约数是（），最小公倍数是（）。6. a=223，b235，则a、b的最大公约数是（），最小公倍数是（）。7.已知x=23a y=2ab,x、y的最大公约数是（ ），最小公倍数是（ ）。8.两个两位数，它们的最大公约数是9，最小公倍数是360，这两个两位数分别是()和( )。选择：1.如果ab=c(a、b、c都是不等于0的自然数)，那么（ ）。a、a是b的倍数 b、b和c都是a的倍数 c、a和b都是c的因数2.已知a、b是两个质数这两个数的最小公倍数是（）。（1）a （2） b （3）ab4.在2，4，7，8，中互质数有（）对。 a.2 b.3 c.4 判断：1.除 1以外的所有非 0的自然数，不是质数就是合数。( )2.互质的两个数一定都是质数。（ ）总结：谈谈这节课的收获？学生独立完成集体订正。学生独立完成集体订正。独立判断，集体交流。学生交流。板书设计教学反思阳谷县实验小学数学教案 课题数 的 运 算（1）序号55教学 目标1.通过复习使学生进一步系统地理解掌握加、减、乘、除四则运算的意义和计算方法。从而培养学生概括能力与计算能力。2.能综合运用所学的知识和技能解决问题，发展应用意识。教学 重点综合运用所学的知识和技能解决问题，发展应用意识。 探 究 过 程教师活动学生活动一、复习四则运算的意义1.举例说明四则运算的意义根据下面算式，说一说它们表示的四则运算的意义23 0.60.423 62 9015 20.30.60.2 0.20.3 提问：看一看，整数、小数、分数的哪些意义相同？哪些意义有扩展？（加法、减法和除法意义相同，乘法意义在小数和分数中有所扩展）师：你能用图示的形式表示出四则运算的意义之间的关系吗？二、复习四则运算法则1.加法和减法的法则 学生交流。学生交流。学生交流。教师活动学生活动探究过程（1）出示三道题，请分析错误原因并改正错误分别是：数位没有对齐，小数点没有对齐，没有通分（2）三条法则分别是怎样要求的？整数：相同数位对齐小数：小数点对齐分数：分母相同时才能直接相加减思考：三条法则的要求反映了一条什么样的共同的规律？（相同计数单位上的数才能相加或相减）2.乘法和除法的法则（1）出示两道题：422341823口述整数乘法和除法的计算法则改编成小数乘除法计算：0.422.348.223 4.822.3（要求：学生在整数计算的结果上确定小数点的位置）（2）提问：通过上面的计算，你发现小数乘法和除法与整数乘法和除法有什么相似的地方？有什么不同？学生交流。学生交流。学生独立计算后交流计算法则。学生独立计算后说说计算法则。学生交流。教师活动学生活动 探究过程（3）说说分数乘法和除法的法则分数乘法和除法比较又有什么相似和不同？三、综合练习。1.计算后说说各题计算时需要注意什么？73.063.9637.51.038.70.03 3.1315（得数保留三位小数）2.根据43783354，直接写出下面各题的得数（复习积的变化规律和商不变的性质）430.780.437.833.540.7833540.433.思考：7.60.25的商与7.64的积相等吗？为什么？4.选择。10.96.2的商四舍五入精确到百分之一是（ ）。a. 0.17 b. 1.75 c. 1.80 d. 1.76ab3（a.b都大于0），则（ ）a. ab b. ab c. ab总结：谈谈这节课的收获？学生交流。学生独立计算后，交流自己的想法。学生独立思考，集体交流。学生独立思考，集体交流。学生独立完成，集体交流。学生交流。板书设计教学反思阳谷县实验小学数学教案 课题数的运算（2）序号56教学 目标1.通过复习使学生熟练地掌握四则运算定律和性质，并能根据题目灵活运用这些知识使计算简便。2.使学生能正确地掌握整数、小数、分数四则混合运算顺序，并能熟练地进行计算。教学 重点能根据题目灵活运用这些知识使计算简便。 探 究 过 程教师活动学生活动一、回顾与交流。1.我们学过哪些运算定律和运算性质？学生交流后教师板书在表格里。名称举例用字母表示加法交换律加法结合律乘法交换律乘法结合律乘法分配律连减的性质连除的性质 学生回顾并与同学交流。教师活动学生活动探究过程2.算一算。 计算：2.512.548 =(2.54)(12.58)应用乘法交换律、结合律计算：4 =4应用乘法分配律计算：（21- =21应用乘法分配律计算：5.03-2.14-1.86 =5.03-(2.14+1.86)应用连减的性质计算：25.4205 =25.4（205）应用连除的性质3.混合运算.(1)说一说整数四则混合运算顺序.算一算:(710-184)2 =(710-72)2=6382=319学生先独立计算，然后交流应用了什么运算定律。学生先独立计算，然后交流应用了什么运算定律。学生先独立计算，然后交流应用了什么运算定律。学生先独立计算