“数怎么不够用了”双语教学教案(教师用)北师大七年级上.docx

编者按： 根据根据学校办学“多元化”、“国际化”的思路，中学部为适应开设国际文凭（IB、AP）班、中加实验班的需要，倡导教师用双语进行教学这里选登了吴娜老师用双语编写的一节数学课的教案与学案，以此推动中学部双语教学的开展教学内容(Teaching content)：北师版七年级上册 第二章第一节“数怎么不够用了”（教案）§2.1 Why are not the numbers enough?（teaching plan）成都美视国际学校 中学部数学组 吴娜（编）教学目标(Teaching objective)：认知目标（Recognize Objective ）：借助生活中的实例理解有理数的意义，体会负数引入的必要性和有理数应用的广泛性能力目标（Objective of ability）：会判断一个数是正数还是负数，能应用正负数表示生活中具有相反意义的量能用简单的英语在课堂上进行交流情感目标（Objective of feeling）：让学生通过对负数及正数，还有0的认识，进一步体会有理数与生活的紧密性，发展学生热爱生活的情感教学重点(Teaching key points)：认识负数及有理数的分类。

教学难点(Teaching difficulties)：有理数的分类及如何表示生活中具相反意义的量；如何用英语正确表述各关键词----有理数、正数、负数、零等等教学过程(Teaching procedures)：1． (Channel into the new lesson)引入新课：(cards)若有一次知识竞赛，其评分标准是，答对一题加10分，答错一题扣10分，不回答得0分，每个队基本分均为0分，四个代表队答题情况如下表：If there is a knowledge competition , the standard of grading is: you will get 10 marks if your answer is right and lose 10 marks if your answer is wrong , no additional mark if you don’t answer any questions. Each team has 0 mark at the beginning. A table of results for the four teams is as below:NO。

1NO5Team 1加10分扣10分加10分加10分扣10分Team 2扣10分加10分不加不扣加10分加10分Team 3加10分加10分扣10分扣10分不加不扣Team 4加10分扣10分加10分扣10分扣10分⑴Answer questions: What is the final mark of each team ? Can you express it? Please discuss it with your partners for3 minutes.⑵ Fill in the table.NO5Final marksTeam 1Team 2Team 3Team 42. New lesson（新课）Part 1: Definitions and expressions⑴ Each positive number is greater than zero.: (Examples: 3, +, , 87.9 ,+ 0.2 , ,……⑵ Each negative number is less than zero :( Examples: , , , ,…….) The history of negative number: 世界上至今发现的最早最详细记载负数的书是《九章算术》，它是由公元3世纪，我国数学家刘徽所著。

在国外，负数概念的建立和使用经历了一个曲折的过程，在欧洲最早承认负数的是17世纪法国数学学家笛卡儿，他承认解方程中出现的负根⑶ Zero is a neither positive number nor a negative numberPart 2: Let students do some practices.” Funny moving” on the blackboard.( Magnets)Part 3: Examples1. In one knowledge competition, if +10 indicate that someone gets 10 marks, then how to indicate that someone loses 20 marks? 在知识竞赛中，如果用+10分表示加10分，那么扣20分怎样表示？2. Xiao Ming rotates the turntable. If +5 indicate that the rotation is in a counter clock wise direction, then how to express the rotation is in a clockwise for 12 circles?小明转动转盘，如果用+5圈表示沿逆时针方向转了5圈，那么沿顺时针方向转了12圈怎样表示？3. In one pingpong quality monitoring test, one pingpong ball is above standard level of 0.02 kilograms, then write +0.02 kilograms. So how would you express －0.03 kilograms?在一次乒乓球质量检测中，一只乒乓球超出标准质量0.02克记作+0.02克，那么－0.03克表示什么？Part 4: Exercise① If the temperature is , then write +. How would you write minus ?如果零上记作+，那么零下，应如何记？② If you use －4 meters to indicate that a person has backed up 4 meters, then how would you express +2 meters? How would you express a person not moving?如果用－4米表示一个人后退了4米，那么+2米表示什么？人原地不动又记为什么呢？③ If you use +50 yuan to express that you’ve made 50 yuan, then what would －35 yuan mean?如果用+50元表示赚了50元，那么－35元表示什么意思？④ If an airplane rises 8000 meters, then drops 5000 meters , so how many meters has it risen?飞机上升8000米，再上升－5000米（下降5000米），则飞机实际上升了多少米？⑤ If a person who walks 40 meters south, then walks 40 meters north, then how many meters has this person actually walked ? Where is this person’s location ?一个人向南走40米，又向北走40米，那么此人实际走了多少米？他的位置是在哪里？⑥ If a person who comes from area A is walking 12 meters east, then walks －15 meters, then again walks +13 meters. Could you tell me where the person is at this time?若向东走8米，记作+8米，如果一个人从A地出发向东走12米，再走－15米，又走了+13米，你能判断此人这时在何处吗？Question: 假设a是一个数，那么怎么表达a是一个正数、负数或者是0？+a一定表示一个正数么？-a一定表示一个负数吗？If ‘a’ is a number, how to express ‘a’ as a positive number ,negative number or zero? Is ‘+a’ a positive number? Is ‘-a’ a negative number?Part 5: Now we know positive number, negative number , and zero. We put these numbers together, and we call it “rational number”. So we know more numbers now. Can you classify these numbers ? 正整数 （positive integer）整数(integer) 零 (zero) 负整数 (negative integer) 正分数 (positive fraction)分数(fraction) 负分数 (negative fraction)整数和分数统称为有理数（rational number）. Well, can you think a good way to classify rational number? Just try your best. Answer this question in English. Teacher write the answer on the blackboard in English. Positive rational numberRational number zero Negative rational number integerRational number fraction3. Summary (总结) Have the students summarize the whole lesson, what did you learn from this lesson? Try to answer questions in English.Appendix(附录): ⑴ Prepare some cards, and write down different kinds of numbers , English expressions. ⑵ Prepare some magnets with some numbers on them, they should。