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人教版新目标初中英语九年级下册By the time I got outside, the bus had already left教案

  • 人教版高中英语必修1English around the world说课稿

    人教版高中英语必修1English around the world说课稿

    (3)v. 给:提出;展现,显现present sb. with sth. ; present sth. to sb. 把. . 交给;颁发;授予present sth. (for sth. )/present sth. to sb. e. g. Om his birthday, his friends presented him a collection of stamps. 在他生日时,他的朋友们送给他一套邮票作为礼物。The sword was presented by the family to the museum. 这家人把宝剑捐赠给了博物馆。The committee will present the final report to Parliament in June. 委员会将在六月向议会提交最后的报告。You need to present yourself better. 你需要更善于展现自己。It is essential that we present a united front. 至关重要的是我们要表现得更加团结。Step 4 ConsolidationT:Now that we have got a general idea of these words and phrases. Lets make up some sentences using them to master them. Suggested sentences:1. Your duties include typing letters and answering the telephone. 2. It is one of the greatest roles that she has played. 3. A large number of people have applied for the job. 4. The number of the panda is declining. 5. I'11 go there, even if I have to walk. 6. He came up to me to ask for a light. 7. The novel is about a family who can't communicate with each other. 8. He based his plan on interests of most people. 9. Why doesn't he make use of his singing talent?Step 5 Summary and homeworkT:Today we dealt with several new words and phrases. After class I hope that youcan read them again and again to keep them in mind. That's all for today. You aredismissed.

  • 人教版高中英语必修2The Olympic Games说课稿2篇

    人教版高中英语必修2The Olympic Games说课稿2篇

    Purpose of my design:To ask the students to do these two tasks will make the Ss predict the story of this passage. As a result, it will deepen Ss’ memory of this story because they will have their own understanding of this story.Step 3. While-readingTask 1. (Individual work _____min)Skimming: ask students to skim the text and the main ideas of each paragraph in this passage. Please read it quickly and then match the sentences with the letters.Task 2. (Individual work _____min)Scanning: read the text quickly and decide the whether the following statements are true or false and give reasons.Task 3. (Pair work _____min)Listen to the tape and fill in the banks. Then read the paragraph with expression to your partner.Task4 (individual work min)Listen to the tape again and write down the main idea in one sentence.Purpose of my design: Enable students to understand the given material better by using different reading skills. And proper competition can arouse the Ss’ interest in English learning. “Task-based” teaching method is used here todevelop the Ss’ ability of communication and also their ability of co-operation will be well trainedStep 4. Post-readingTask 1. (Individual work, pair work, group work, class work; _____min)Discussion (group of 4):1. If you were Hippomenes, would you run against Atlanta?2. Do you think Hippomenes deserved to win the race? Why or why not?Step 5. HomeworkPlease read the story again carefully after class and imagine: What will happen during the race between Hippomenes and Atlanta? Who do you think will win the race? Do you think Atlanta would marry Hippomenes? Write an end for the story with thses questions.Purpose of my design: Homework is so important and necessary for to master the knowledge they learned after class. It will check whether the Ss achieve the teaching aims.Part 5 Blackboard design

  • 人教版高中英语必修3Canada-the true north说课稿4篇

    人教版高中英语必修3Canada-the true north说课稿4篇

    Good afternoon, teachers, It’s my great pleasure to be here sharing my lesson with you.The content of my lesson is Senior English Book 3 Unit 5 Canada —— “The true North”.I’ll be ready to begin this lesson from five parts. Analysis of the teaching material,the teaching methods,the studying methods, the teaching procedure,and Blackboard design.First, let me talk about the teaching material.Part 1 Teaching Material:This unit is about the introduction of Canada. By studying of this unit,we’ll enable the students to learn the geography, population, main cities, and natural beauty, natural resources of Canada. Through the training of the unit, it also requires students to learn some Language skills such as the expressions of position and emotions.So it plays an important part in the English teaching in this book.After studying the teaching material and analyzing the rule of children’s growing of mind,I think the teaching aims are the followings:1.Knowledge objects:(1) make the students learn some new words and phrases(2) make the students understand the content of the lesson.2.Ability objects:(1)To develop the Ss’ abilities of listening, speaking, reading and writing. Especially reading and speaking ability.(2) learn to talk about the characters of Canada in English(3)To train the Ss’ ability of working in pairs.3.Emotion objects:(1)Enable students to understand the characters of Canada..(2)Stimulate Ss to work hard to make China stronger.Part 2 Teaching Methods:I think helping students learn to master new words and phrases and improve the students’ reading and speaking ability is import and the difficult.According to the analysis of the teaching material and the import points and the difficult points,I will use the following teaching methods : question-guiding approach; fast-reading and careful reading; multi-media teaching methods; discussion

  • 人教版高中英语必修3Festivals around the World说课稿3篇

    人教版高中英语必修3Festivals around the World说课稿3篇

    Teaching plan for Unit 1 book3Good morning, teachers. It’s my great pleasure to be here because I can share my lesson with you and I can learn a lot from it. I’ll begin my lesson from the following four parts, the teaching material, the teaching methods, the studying methods and the teaching procedure.Firstly, let me talk about the teaching material. The content of my lesson is the reading passage festivals and celebrations of Unit 1 Festivals around the world. This passage is about festivals and celebrations. By studying this passage, we’ll enable the students to know that festivals exit everywhere, and many of festivals in different countries celebrate similar ideas. As we all know, the reading passage is the center of each unit. If the Ss can learn it well, it will be helpful to make the Ss learn the rest of this unit.After studying the teaching material, I think the teaching aims are as the followings:1. Knowledge aims:(1) The Ss can master the usage of the important words andexpressions.(2)The Ss can use the __________________ (grammar) in the proper situation.Make students know about the festivals all over the world and the detail of the festivals, such as origin, content, and the date of the holiday festivals.2. Ability aims:(1) Students can talk about festivals and celebrations in English(2) To improve the student’s reading ability, especially their skimming and scanning ability.3. Emotion aims:Make the Ss know about the foreign festivals, and respect other countries’ custom.Next, let’s come to the important points and the difficult points.The important point is how to make the Ss understand the text better and the difficult point is how can they talk about it. secondly, Teaching Methods:1. task-based Language Teaching2. Computer assisted language teaching.3. question-and–answer methodThirdly, Studying Methods:

  • 人教版高中英语必修3The million pound bank note说课稿3篇

    人教版高中英语必修3The million pound bank note说课稿3篇

    在接下来的细读环节,我套用了高考对阅读理解的考查方式设置了5个问题,分别为三个推理判断题,一个细节题和一个主旨大意题。学生需要对文章的内容进行分析、归纳、推理、猜测等高级思维活动才能做出正确的回答。【设计意图】这一过程是对学生进行细读的训练,培养学生获取特定信息和挖掘文章深层次信息的能力。第三环节:Intensive-reading (精读) 15′第三个环节精读,既是最重要的环节,也是突破本课重难点的关键。首先,让学生思考剧本中人物看到百万英镑前后的态度发生了怎样的变化。其次,让学生仔细阅读文章,找出可以表现人物态度变化的具体的语言和动作。最后,让学生总结人物的态度发生变化的根本原因是什么,从而引出Money Talks, 供学生思考。【设计意图】通过一系列的活动培养学生学习从人物的语言和动作探究人物的心理,使学生进一步体会戏剧语言的魅力,从而对文章背后所反映的社会问题进行思考,也为下一步的讨论环节做好铺垫。

  • 人教版高中英语必修5Making the news说课稿4篇

    人教版高中英语必修5Making the news说课稿4篇

    今天我们来介绍一下必修五第四单元的授课方式。这个单元的题目是Making the news。应该是学生比较感兴趣的话题,学生往往对新闻工作充满好奇,所以我们可以利用这个机会多设计一些师生互动和学生互动,来激发起学习的积极性,提高学习效率。同时我们可以利用这个单元不仅帮助学生掌握语言知识,培养语言能力,同时让其了解新闻工作的重要性,培养起社会智能感。这个单元分为六个课时,它的教学目标是这样的:语言目标是掌握词汇表中的常用单词和短语,掌握倒装句的一些基本用法。 技能目标是能初步掌握约会的基本句型并在真实的场景下正确运用。新闻报道类文章的写作技能。采访的基本规范和沟通技能。情感目标是对新闻报道的客观性和真实性有更好的理解。对新闻记者的职业有更深入的了解,并能体会其工作的重要性。下面我们来介绍一下第一课时的授课方式,第一课的教学目标是这样的第一课时的教学目标语言目标:单词:Occupation, journalist, editor, photographer, curious, personality, enthusiasm

  • 人教版高中英语必修5The United Kingdom说课稿4篇

    人教版高中英语必修5The United Kingdom说课稿4篇

    Teaching Aims:Knowledge 1. Get the students to learn the useful new words and expressions in this section. Aims:2. Let the students learn about how the UK was formed and the four groups of invaders.1. Develop students’ reading ability and let them learn different Ability reading skills. Aims:2. Enable students to learn to talk about the United Kingdom and the Union Jack Emotional 1. Let students know more about the UK2. Develop students’ sense of cooperative learning Aims:Teaching Important Points:1. Let the students learn about the countries of the United Kingdom and the Union Jack2. Get the students to read the passage and know about how the UK was formed and the four groups of invaders.3. Have the students learn different reading skills.Teaching Difficult Ponts:1. Develop students’ reading ability.2. Enable students to talk about the United Kingdom and the Union Jack.3. Let students learn how the UK was formed geographically and historically.Teaching Methods:Showing pictures, asking, exercising, listening, reading etc.Teaching Aids:A computer,a projector and a blackboard.Teaching Procedures: 1) Show a map of the world, ask students the following questions:Where is the UK?What’s the full name of the UK?2) Ask the students work in pairs to do the quiz on Page 9.Do you want to test how many things you know about the United Kingdom? Let’s have a small test.Using the map on P9, students answer the following questions:?How many countries does the UK consist of? What are they??England is divided into three main areas. Do you know what they are? 1) Scanning (10Minutes )Let the students hold the questions asked in pre-reading and read the passagequickly and then let them do the following exercise.Join lines to the right answer.

  • 人教版高中英语必修4Working The Land说课稿3篇

    人教版高中英语必修4Working The Land说课稿3篇

    Knowledge objectives:(1) to make Ss grasp the usage of words, expressions and sentence structures: statistics, struggle, thanks to, rid of, some patterns for persuasion, the “ing” form as subject and object;(2)to use learnt knowledge to persuade sb.Ability objectives:(1) to develop Ss’ reading skills(skimming, scanning, word guessing);(2) to improve Ss’ speaking, communicating and cooperating skills.Emotional objectives:to make Ss know the contribution of Yuan,and learn his spirit and his simple life time.Teaching important and difficult points:(1) some words, expressions and sentence structures mentioned above;(2)the content of the text;(3)training their reading and speaking skills.Teaching methods: CLT, TBLT,QT.Learning strategies: CLS, QLS, TBLS.Teaching procedures:Step 1 lead-in: (1) teacher plays a piece of recent news from CCTV about the harvest of the super hybrid rice, and ask students whether they know Yuan or not, and talk about him and his contribution.(2)Brain storm: let Ss describe Yuan in their minds including his appearance, his living condition and so on.Step 2 fast reading tasks:(1)teacher introduces Yuan and super hybrid rice(2)make Ss read the text as fast as possible with questions. Such as: what’s the general ideaof this passage? What’s Yuan’ dream? (skimming and scanning skill)Step 3 intensive reading tasks(1)let Ss read the text silently, find topic sentence of each paragraph and draw the difficult sentences and the knowledge what they don’t understand.(words guessing)(2)teacher and Ss talk about the important words, expressions and sentences together, and ask Ss to retell the content of the text.(summarizing and paraphrasing)(3)teacher summarize this part.(4) read again following the courseware.

  • 人教版高中英语必修5Life in the Future说课稿5篇

    人教版高中英语必修5Life in the Future说课稿5篇

    Good afternoon, everyone. It’s my great pleasure to be here sharing my lesson with you. The content of my lesson is Senior English for China Book5 Unit 3 Life in the Future. I’ll be ready to begin this lesson from six parts: Analysis of the teaching material, Analysis of the students, Teaching aims and important and difficult points, Teaching methods and aids, Teaching procedures, and Blackboard design. First, let me talk about the teaching material.Part 1 Analysis of the Teaching Material:This unit is about what human beings’ life will be like in about one thousand years. By studying of this unit, we’ll Enable the students to know the changes in humans’ life and some new inventions bringing about the change and develop the interest in science. This lesson plays an important part in the English teaching in this unit. This is an important lesson in Book Five. From this lesson, it starts asking the Ss to grasp contents of each passage. Therefore, this lesson is in the important position of the teaching material. If the Ss can learn it well, it will be helpful to make the Ss learn the rest of this unit.Part 2 Analysis of the SsAs Senior2 Ss, they are at different levels of English fluency, some of them have lost interest in English. So during the lesson, I arrange a variety of activities to let all of them join in to attract their interest and let them be confident and taste the joy of success.

  • 人教版新课标小学数学一年级下册两位数减一位数和整十数(不退位)教案

    人教版新课标小学数学一年级下册两位数减一位数和整十数(不退位)教案

    一、教学内容:两位数减一位数和整十数(不退位)(课本第67页)。二、教学目标:1、知识与技能:让学生经历探索两位数减一位数和整十数(不退位)的计算方法的过程,掌握计算方法,能正确地口算。2、过程与方法:让学生经历自主探索、动手操作、合作交流等方式获得新知的过程,积累数学活动的经验,体会数学知识与日常生活的密切联系,增强应用意识。3、情感态度与价值观:进一步培养学生学习数学的热情,以及积极思考、动手实践并与同学合作学习的态度。三、教学重点:掌握两位数减一位数和整十数(不退位)的口算方法。四、教学难点:理解算理,把握两位数减一位数与两位数减整十位数在计算过程中的相同点与不同点。五、教具准备:课件、题卡、等。六、教学过程:(一)、创设情境,提出问题。

  • 人教版新课标小学数学三年级下册一位数除三位数(商是两位数且有余数)教案2篇

    人教版新课标小学数学三年级下册一位数除三位数(商是两位数且有余数)教案2篇

    二、互动交流,理解算法1.出示教科书第22页的情境图,提问:他们在干什么?你获得了什么信息?能提出什么问题?怎样列式?2.师:今天我们就学习一位数除三位数的计算方法。(板书课题:一位数除三位数)3.师:怎样计算238÷6呢?你能用估算的方法估计出大致结果吗?4.学生尝试独立完成例3的竖式计算。师:在这道题中被除数最高位上是2个百,2个百除以6,商不够1个百怎么办?师:谁能说一说商3个十的3写在商的什么位置上?为什么?教师边板演边说明:用除数6去乘3个十,积是18个十,表示被除数中已经分掉的数,写在23的下面。23减18得5,表示十位上还剩5个十。师:接下来该怎么办?(把被除数个位上的8落下来,与十位上的5合起来继续除。)师:最后结果是多少?5.启发学生想一想:如果一本相册有24页,一本相册能插得下这些照片吗?2本呢?

  • 人教版新课标小学数学一年级下册两位数减一位数的退位减法教案

    人教版新课标小学数学一年级下册两位数减一位数的退位减法教案

    2.送信。实物投影仪演示反馈。(1)方法说明。你是怎么想的?(2)错误纠正。分层校对:做完的先互相批改,然后集体先校对丁当组题,再校对一休组题。重点讲评一休组题目。六、总结今天你有哪些收获?(1)退位减法要注意什么?不要忘记退位。(2)退位减法的方法。为学生提供学习材料,让学生通过活动联系生活实际学习新知,让学生感受到数学源于生活,用于生活;采用分层教学,整个学习过程都是学生在小组中合作研究、探索中完成的;然后通过多种形式的练习加以巩固;注重学习过程的开放;通过小组合作,培养学生善于发表自己的观点,会倾听同学的意见的能力。同时也培养学生学会提出问题、解决问题的能力。

  • 人教版新课标小学数学五年级下册整数加法运算定律推广到分数加法教案

    人教版新课标小学数学五年级下册整数加法运算定律推广到分数加法教案

    教学目标1、通过教学,学生懂得应用加法运算定律可以使一些分数计算简便,会进行分数加法的简便计算.2、培养学生仔细、认真的学习习惯.3、培养学生观察、演绎推理的能力.教学重点整数加法运算定律在分数加法中的应用,并使一些分数加法计算简便.教学难点整数加法运算定律在分数加法中的应用,并使一些分数加法计算简便.教学过程设计一、复习准备(演示课件:整数加法运算定律推广到分数加法)下载1.教师:整数加法的运算定律有哪几个?用字母怎样表示?板书:a+b=b+a(a+b)+c=a+(b+c)2.下面各等式应用了什么运算定律?①25+36=36+25 ②(17+28)+72=17+(28+72)③6.2+2.3=2.3+6.2 ④(0.5+1.6)+8.4=0.5+(1.6+8.4)教师:加法交换律和结合律适用于整数和小数,是否也适用于分数加法呢?这节课我们就一起来研究.二、学习新课(继续演示课件:整数加法运算定律推广到分数加法)下载1.出示:下面每组算式的左右两边有什么关系?

  • 新人教版高中英语必修3Unit 5 The Value of Money-Discovering Useful Structures导学案

    新人教版高中英语必修3Unit 5 The Value of Money-Discovering Useful Structures导学案

    4.They were going to find someone to take part in their bet when they saw Henry walking on the street outside.[归纳]1.过去将来时的基本构成和用法过去将来时由“would+动词原形”构成,主要表示从过去某一时间来看将要发生的动作(尤其用于宾语从句中),还可以表示过去的动作习惯或倾向。Jeff knew he would be tired the next day.He promised that he would not open the letter until 2 o'clock.She said that she wouldn't do that again.2.表示过去将来时的其他表达法(1)was/were going to+动词原形:该结构有两个主要用法,一是表示过去的打算,二是表示在过去看来有迹象表明将要发生某事。I thought it was going to rain.(2)was/were to+动词原形:主要表示过去按计划或安排要做的事情。She said she was to get married next month.(3)was/were about to+动词原形:表示在过去看来即将要发生的动作,由于本身已含有“即将”的意味,所以不再与表示具体的将来时间状语连用。I was about to go to bed when the phone rang.(4)was/were+现在分词:表示在过去看来即将发生的动作,通常可用于该结构中的动词是come,go,leave,arrive,begin,start,stop,close,open,die,join,borrow,buy等瞬间动词。Jack said he was leaving tomorrow.

  • 北师大初中七年级数学上册应用一元一次方程——“希望工程”义演教案1

    北师大初中七年级数学上册应用一元一次方程——“希望工程”义演教案1

    方法总结:解题关键是要读懂题目的意思,根据题目给出的条件,找出合适的等量关系,列出方程再求解.探究点三:工程问题一个道路工程,甲队单独施工9天完成,乙队单独做24天完成.现在甲乙两队共同施工3天,因甲另有任务,剩下的工程由乙队完成,问乙队还需几天才能完成?解析:首先设乙队还需x天才能完成,由题意可得等量关系:甲队干三天的工作量+乙队干(x+3)天的工作量=1,根据等量关系列出方程,求解即可.解:设乙队还需x天才能完成,由题意得:19×3+124(3+x)=1,解得:x=13.答:乙队还需13天才能完成.方法总结:找到等量关系是解决问题的关键.本题主要考查的等量关系为:工作效率×工作时间=工作总量,当题中没有一些必须的量时,为了简便,应设其为1.三、板书设计“希望工程”义演题目特点:未知数一般有两个,等量关系也有两个解题思路:利用其中一个等量关系设未知数,利用另一个等量关系列方程

  • 北师大初中七年级数学上册有理数的加减混合运算的实际应用教案

    北师大初中七年级数学上册有理数的加减混合运算的实际应用教案

    (1)本周哪一天河流水位最高,哪一天河流水位最低,它们位于警戒水位之上还是之下,与警戒水位的距离分别是多少?(2)与上周末相比,本周末河流的水位是上升还是下降了?解析:(1)先规定其中一个为正,则另一个就用负表示.理解表中的正负号表示的含义,根据条件计算出每天的水位即可求解;(2)只要观察星期日的水位是正负即可.解:(1)前两天的水位是上升的,第1天的水位是+0.20米;第2天的水位是+0.20+0.81=+1.01米;第3天的水位是+1.01-0.35=+0.66米;第4天的水位是+0.66+0.13=+0.79米;第5天的水位是0.79+0.28=+1.07米;第6天的水位是1.07-0.36=+0.71米;第7天的水位是0.71-0.01=+0.7米;则水位最低的是第一天,高于警戒水位;水位最高的是第5天;(2)+0.20+0.81-0.35+0.13+0.28-0.36-0.01=+0.7米,则本周末河流的水位上升了0.7米.方法总结:解此题的关键是分析题意列出算式,用的数学思想是转化思想,即把实际问题转化成数学问题.探究点二:有理数的加减混合运算在生活中的其他应用

  • 北师大初中数学八年级上册应用二元一次方程组——里程碑上的数1教案

    北师大初中数学八年级上册应用二元一次方程组——里程碑上的数1教案

    A、B两码头相距140km,一艘轮船在其间航行,顺水航行用了7h,逆水航行用了10h,求这艘轮船在静水中的速度和水流速度.解析:设这艘轮船在静水中的速度为xkm/h,水流速度为ykm/h,列表如下,路程 速度 时间顺流 140km (x+y)km/h 7h逆流 140km (x-y)km/h 10h解:设这艘轮船在静水中的速度为xkm/h,水流速度为ykm/h.由题意,得7(x+y)=140,10(x-y)=140.解得x=17,y=3.答:这艘轮船在静水中的速度为17km/h,水流速度为3km/h.方法总结:本题关键是找到各速度之间的关系,顺速=静速+水速,逆速=静速-水速;再结合公式“路程=速度×时间”列方程组.三、板书设计“里程碑上的数”问题数字问题行程问题数学思想方法是数学学习的灵魂.教学中注意关注蕴含其中的数学思想方法(如化归方法),介绍化归思想及其运用,既可提高学生的学习兴趣,开阔视野,同时也提高学生对数学思想的认识,提升解题能力.

  • 北师大初中七年级数学上册利用移项与合并同类项解一元一次方程教案2

    北师大初中七年级数学上册利用移项与合并同类项解一元一次方程教案2

    练习:现在你能解答课本85页的习题3.1第6题吗?有一个班的同学去划船,他们算了一下,如果增加一条船,正好每条船坐6人,如果送还了一条船 ,正好每条船坐9人,问这个班共多少同学?小结提问:1、今天你又学会了解方程的哪些方法?有哪些步聚?每一步的依据是什么?2、现在你能回答前面提到的古老的代数书中的“对消”与“还原”是什么意思吗?3、今天讨论的问题中的相等关系又有何共同特点?学生思考后回答、整理:① 解方程的步骤及依据分别是:移项(等式的性质1)合并(分配律)系数化为1(等式的性质2)表示同一量的两个不同式子相等作业:1、 必做题:课本习题2、 选做题:将一块长、宽、高分别为4厘米、2厘米、3厘米的长方体橡皮泥捏成一个底面半径为2厘米的圆柱,它的高是多少?(精确到0.1厘米)

  • 北师大初中七年级数学上册应用一元一次方程——水箱变高了教案2

    北师大初中七年级数学上册应用一元一次方程——水箱变高了教案2

    从而为列方程找等量关系作了铺垫.环节2中的表格发给每个小组,为增强小组讨论结果的展示起到了较好的作用.环节3中通过让学生自己设计表格为讨论的得出起到辅助作用.2.相信学生并为学生提供充分展示自己的机会本节课的设计中,通过学生多次的动手操作活动,引导学生进行探索,使学生确实是在旧知识的基础上探求新内容,探索的过程是没有难度的任何学生都会动手操作,每个学生都有体会的过程,都有感悟的可能,这种形式让学生切身去体验问题的情景,从而进一步帮助学生理解比较复杂的问题,再把实际问题抽象成数学问题.3.注意改进的方面本节课由于构题新颖有趣,所以一开始就抓住了学生的求知欲望,课堂气氛活跃,讨论问题积极主动.但由于学生发表自己的想法较多,使得教学时间不能很好把握,导致课堂练习时间紧张,今后予以改进.

  • 北师大初中七年级数学上册应用一元一次方程——水箱变高了教案1

    北师大初中七年级数学上册应用一元一次方程——水箱变高了教案1

    解:设截取圆钢的长度为xmm.根据题意,得π(902)2x=131×131×81,解方程,得x=686.44π.答:截取圆钢的长度为686.44πmm.方法总结:圆钢由圆柱形变成了长方体,形状发生了变化,但是体积保持不变.“变形之前圆钢的体积=变形之后长方体的体积”就是我们所要寻找的等量关系.探究点三:面积变化问题将一个长、宽、高分别为15cm、12cm和8cm的长方体钢坯锻造成一个底面是边长为12cm的正方形的长方体钢坯.试问:是锻造前的长方体钢坯的表面积大,还是锻造后的长方体钢坯的表面积大?请你计算比较.解析:由锻造前后两长方体钢坯体积相等,可求出锻造后长方体钢坯的高.再计算锻造前后两长方体钢坯的表面积,最后比较大小即可.解析:设锻造后长方体的高为xcm,依题意,得15×12×8=12×12x.解得x=10.锻造前长方体钢坯的表面积为2×(15×12+15×8+12×8)=2×(180+120+96)=792(cm2),锻造后长方体钢坯的表面积为2×(12×12+12×10+12×10)=2×(144+120+120)=768(cm2).

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