第一篇：視頻格式大小比較

視頻格式大小比較？mp4 avi 3gp rmvb wmv mkv mpg vob mov flv按大小排序？

? 樓上說的很正確, 還有一種比較方法, 就是同一個(gè)內(nèi)容用這些格式來壓縮, 然后比較大小, 在網(wǎng)絡(luò)上常見的大小數(shù)序如下, 小到大

flv, 3gp, mp4, mov, mpg, wmv, rmvb, mkv, avi

解釋一下, flv都是那些視頻網(wǎng)站在用, 為了網(wǎng)絡(luò)傳輸, 肯定用最小的大小

3gp是手機(jī)在用, 這個(gè)也肯定不會(huì)太大

mp4都是移動(dòng)設(shè)備在用, ipod和一些手機(jī)和播放器, 大了裝不下的mov是蘋果電腦常用格式, 蘋果向來以效率著稱

mpg其實(shí)很大的, 之所以大家都覺得它小, 是因?yàn)樗窃缙诟袷? 那時(shí)候的電影清晰的不高, 所以mpg的大小也不大

wmv是微軟的, 用這個(gè)格式壓縮的人不多, 很多都是惡意添加許可證, 讓你必須連接到某個(gè)網(wǎng)站

rmvb是最常見的格式, 當(dāng)初是為網(wǎng)絡(luò)傳播設(shè)計(jì)的, 要求很小的大小就能有很高的清晰度, 雖然比不過上面那些, 不過性價(jià)比很高, 用的人很多

mkv是新興的格式, 大小不太了解, 只是電驢上面那些人經(jīng)常用這個(gè)格式壓縮高清影片, 每個(gè)都1G多, 很少見到小的

avi通常是發(fā)布最原始的無壓縮的電影時(shí)用的格式, 大小就是DVD的4.2G, 提供給別人壓縮并添加字幕的 drganfly-二級(jí) 2009-11-11 02:24

? 1.首先要明確 LZ列明的都是封裝格式 不是編碼格式 他們各自都可以封裝特定的數(shù)種編碼格式 只有編碼格式?jīng)Q定文件的大小 封裝格式只是將數(shù)據(jù)打包起來而已

例如: mp4 avi mkv flv mov都可以封裝h264 嚴(yán)格來說就不存在可比性了

2.不過 這些封裝格式大多數(shù)情況下封裝的編碼格式有普遍的特定性 按照同等畫質(zhì)的前提下 各自所需要的數(shù)據(jù)量 可以粗略的排列他們的大小

mpg > 3gp > vob > rmvb > mov > flv > avi = wmv > mp4 = mkv

再次提醒 這是在要達(dá)到同等畫質(zhì)的條件下的文件大小的比較！

3.按照網(wǎng)絡(luò)上流傳的格式 其常見的文件大小來排列的話:

vob > mkv = avi > rmvb > mov = mp4 > flv = 3gp 匿名 2009-11-11 10:05

第二篇：比較大小 教案

比較大小

一、教學(xué)目標(biāo)

1、掌握100以內(nèi)數(shù)的順序，會(huì)比較100以內(nèi)數(shù)的大小。

2、引導(dǎo)學(xué)生獨(dú)立思考，初步學(xué)習(xí)對數(shù)量的估計(jì)，逐步建立數(shù)感，理解多一些、多得多、少一些、少得多的相對性，并能夠用準(zhǔn)確地語言進(jìn)行表述。

3、培養(yǎng)學(xué)生的合作與交流的意識(shí)與能力。

4、激發(fā)學(xué)生的學(xué)習(xí)興趣，發(fā)展思維能力。

二、教學(xué)重難點(diǎn)：

理解多一些、多得多、少一些、少得多的相對性，并能夠用準(zhǔn)確地語言進(jìn)行表述。

三、教學(xué)重難點(diǎn)：

正確熟練地進(jìn)行比較

四、教具準(zhǔn)備；

例4放大圖兩幅、投影片。

五、教學(xué)過程：

（一）、復(fù)習(xí)。

1、讀出下列各數(shù)。35 76 89 90 96 100

2、老師報(bào)數(shù)，學(xué)生在本子上寫數(shù)。六十九 九十三 八十 三十 一百

3、口答。(1)一個(gè)兩位數(shù)，高位上是5，低位上是9，這個(gè)數(shù)寫作()。(2)一個(gè)數(shù)，百位上是l，十位、個(gè)位都是0，這個(gè)數(shù)寫作()。

（二）、新授。

1、教學(xué)例5。

(1)出示小棒圖。教師問：左邊有多少根小棒?右邊有多少根小棒? 根據(jù)學(xué)生回答，教師板書； 42 37 教師追問：“左右兩邊的小棒，哪邊的多?(左邊多)42和37兩個(gè)數(shù)比較。哪個(gè)數(shù)大?”

學(xué)生回答，老師再做說明，42和37相比較，42大，37小，我們用“>”來表示它們的關(guān)系。(2)出示計(jì)數(shù)器圖。(3)讓學(xué)生觀察后問：

“左邊的計(jì)數(shù)器表示多少?右邊的計(jì)數(shù)器表示多少?”學(xué)生回答后，老師板書：23 25．又問：“23和25這兩個(gè)數(shù)相比較，哪個(gè)數(shù)大，哪個(gè)數(shù)小，應(yīng)該怎樣表示?”老師在○里填上“<”大家齊讀式子兩遍。另一幅圖提問個(gè)別學(xué)生誰大于誰?把你的想法說給大家聽一聽。

3、做課本第42頁“做一做”。

先讓學(xué)生獨(dú)立做題，教師巡視指導(dǎo)，對有困難學(xué)生可對照數(shù)目表，做完后集體訂正。

4、投影出示例6．

教師：紅球有幾個(gè)?(58個(gè))藍(lán)球有幾個(gè)?(15個(gè))黃球有幾個(gè)?(10個(gè))大家一起從15數(shù)到58，數(shù)的過程體會(huì)到15到58要經(jīng)過好多的數(shù)。

教師告訴學(xué)生，58比15多得多，象剛才的題目我們就可以說，紅球比藍(lán)球多得多。請一個(gè)同學(xué)從10數(shù)到15，從中感受到l0到15比較接近，我們就可以說15比10多一些，象剛才的題目，我們就可以說黃球比藍(lán)球少一些

5、第43頁“做一做”

根據(jù)題意每人用“多一些、少一些、多得多、少得多”說一句話。

（三）課堂小結(jié)

大家說說今天有什么收獲？

六、教學(xué)板書

生活中哪些地方用到了“多一些、多得多、少一些、少得多”這樣的詞語？

第三篇：大小作文

2011

1、小作文：

Directions: Some international students are coming to your university.Write them an email in the name of the Students' Union to

1)extend your welcome and

2)provide some suggestions for their campus life here.You should write about 100 words on ANSWER SHEET2.Do not sign your own name at the end of the letter, Use “Li Ming” instead.Do not write the address.(10 points).Dear Friends, On behalf of the Students’ Union of Beijing Foreign Studies University, I would like to extend our heartfelt welcome to all of the overseas students from all over the world to study in our university.It is my great pleasure to propose several practical suggestions to you.In the first place, life in this prestigious university perhaps is not as satisfactory as what you expected.You may be tightly bound by continual classes, excessive homework and exams.In the second place, in spite of all these adversities, you will still enjoy your life in this esteemed institution.All types of extracurricular activities such as sports meets, speech contests, different social gatherings and dancing parties provide ample opportunities to make friends.All in all, although there are many things lacking, life in our campus is a worthwhile period in your whole lifetime.Wish you enjoy your life here!Yours sincerely, Li Ming 親愛的朋友們：

謹(jǐn)代表北京外國語大學(xué)學(xué)生會(huì)，向來我校學(xué)習(xí)的世界各地的海外學(xué)生表達(dá)衷心的歡迎。

我很榮幸地向你們提出一些實(shí)用的建議。首先，這所著名學(xué)府的生活也許不像你們所期待的那么令人滿意。你們可能會(huì)陷入無盡的課程、大量的作業(yè)和考試。其次，盡管有這些課業(yè)，你們?nèi)詫⑾硎苓@所大學(xué)的生活。運(yùn)動(dòng)會(huì)、演講比賽、聯(lián)誼會(huì)和舞會(huì)等各種各樣的課外活動(dòng)提供大量交朋友的機(jī)會(huì)。

總之，盡管有很多不足，我們的校園生活仍將是你一生中一段美好的歲月。希望你享受這里的生活！

您真誠的，李明

2、大作文：

Directions: Write an essay of 160-200 words based on the following drawing.In your essay, you should 1)describe the drawing briefly.2)explain its intended meaning, and 3)give you comments.You should write neatly on ANSWER SHEET2.(20 points)參考范文

As is symbolically illustrated in the cartoon, two individuals respond to the same event in completely diverse ways.The person on the left airs his dissatisfaction and disappointment when a bottle is overturned, while the man on the right is hurry to raise it up, with a sweet smile on his face.We are informed that various folks take different attitudes toward the same scene.The aim of the portrayal is to illustrate that keeping optimistic is of utmost significance to both our society and our life.In the first place, as an extremely vital psychological quality, optimism brings us creative power to play, arouses our enthusiasm for work and helps us overcome difficulties.In other words, with pessimism, achievements can hardly be made.In the second place, keeping optimistic gives us light when we are in dark and encouragement when we are dismayed.It is optimism, rather than genius and extraordinary ability, that inspires us to cope with any arduous task.With optimism, the goal we intend can be reached, and so can the hard nut be cracked.In conclusion, keeping optimistic encourages people to learn wisdom, humanity and self-confidence, and is a crucial and unavoidable aspect of any individual’s development of character and competence.參考譯文：

如圖所示，兩個(gè)人對同一件事情的反應(yīng)截然相反。當(dāng)瓶子倒下時(shí)，左邊的人表達(dá)了不滿和失望，然而右邊的人卻面帶微笑，急著把它扶起來。我們得知不同的人對同一事物看法不同。

這幅漫畫的目的是闡明保持樂觀對于我們的社會(huì)和生活都至關(guān)重要。首先，作為一種極為重要的心理素質(zhì)，樂觀給我們的娛樂帶來了創(chuàng)造力，點(diǎn)燃了我們對于工作的熱情，幫助我們克服困難。換而言之，如果悲觀，我們很難取得任何成績。其次，在我們身處黑暗時(shí)，樂觀帶來光明；在我們沮喪灰心時(shí)，樂觀賦予勇氣。正是樂觀，而非天才或卓越的才能，激勵(lì)我們應(yīng)對任何艱難險(xiǎn)阻。擁有樂觀，我們才能實(shí)現(xiàn)計(jì)劃中的目標(biāo)，并且克服困難。

總之，保持樂觀可以鼓勵(lì)人們?nèi)W(xué)會(huì)獲得智慧、博愛和自信，因此是個(gè)人性格和能力的培養(yǎng)過程中不可缺少的重要組成部分。2011 Part A: 小作文

Directions:

Write a letter to a friend of yours to

1)recommend one of your favorite movies and

2)give reasons for your recommendation.You should write about 100 words on ANSWER SHEET 2.Do not sign your own name at the end of the letter.Use”Li Ming”instead.Do not write the address.(10 points)Dear Bob, As one of your closest friend, I'm writing the letter in purpose of recommending one of my favorite movies to you, Around the World in Eighty Days.The primary factors for my recommendation as as follows.For one thing, this is a movie of science fiction which tells us an exciting story about an English gentleman,Mr.Phileas Fogg, who makes a bet with his clubmates and managers to travel around the world in eighty days.For another, it gives us a vivid description of the many difficulties and incidents which happen on his journey.Wish you enjoy the movie.Looking forward to your reply.(104 words)Yours sincerely, Li Ming

參考譯文

鮑勃：

作為你最好的一位朋友，我寫這封信是為了向你推薦我最喜歡的電影之一：《八十天環(huán)游地球》。

我推薦的主要原因如下。首先，這是一部科幻電影，講述了一位英國紳士的一個(gè)激動(dòng)人心的故事。菲力·弗格先生跟他的俱樂部伙伴打了個(gè)賭，并設(shè)法在八十天之內(nèi)環(huán)游了地球。其次，電影生動(dòng)描述了他在旅途中遇到的困難和發(fā)生的故事。

希望你喜歡這部電影。期待著你的回信。

你真誠的，李明

Part B: 大作文 Direction: Write an essay of 160-200 words based on the following drawing.In your essay ,you should 1)describe the drawing briefly, 2)explain its intended measing, and 3)give your comments.You should write neatly on ANSWER SHEET 2.(20 points)As is subtly portrayed in the cartoon, two tourists are taking sightseeing on a small boat while discarding their picnicing leftovers casually into a lake.Unfortuantely, the lake is already littered and teamed with flowing rubbish like plastic containers, fish-bones, banana skin, watermelon rind, bottles, tins, food wrappings, and so on.And below the drawing, there is a topic which says: “after” the travel or “me” in the travel.From the portrayal, we can conclude that the painter wants to convey such a message: a good many popular places are flooded with visitors, who spoil the beauty of nature by creating and leaving behind God-knows-how-much trash.On the one hand, tourism, as a multibillion-dollar business, is booming everywhere.Some people, laboring under the belief that tourism serves as an engine of economic growth, seem to ignore its negative effects on the environment.Nevertheless, it is my view that these are not concerns that we can shrug off lightly.On the other hand, tourism has exerted great pressure on the environment we are living in: water is polluted, the ecological system is disturbed, and natural resources have been excessively used.Undoubtedly, tourism could not be banned in any country as it does help to shore up the economy in places which offer few sources of income.The significant point is that the unchecked growth of the travel business may render the development of an economy unsustainable.It is high time that we enhanced people's awareness to rectify this by taking the environmental protection into consideration.(255 words)參考譯文

如圖所示，兩名游客正在一艘小船上觀光，同時(shí)把野餐的剩余垃圾隨意丟入湖中。不幸的是，湖中已經(jīng)堆滿了漂浮的塑料盒、魚骨、香蕉皮、西瓜皮、瓶子、罐頭、食品包裝等各色垃圾。在圖畫下方，有個(gè)小標(biāo)題寫明：“旅程之‘余’”。從漫畫中，我們可以得出結(jié)論：畫家想要表達(dá)下述信息：成群的游客涌入很多景點(diǎn)，通過生產(chǎn)并丟棄大量的垃圾從而破壞了大自然的美觀。一方面，旅游業(yè)作為一項(xiàng)數(shù)十億美元的產(chǎn)業(yè)，正在世界各地迅猛發(fā)展。有些人認(rèn)為旅游業(yè)是經(jīng)濟(jì)發(fā)展的引擎，似乎忽視了其對環(huán)境的負(fù)面影響。然而，我認(rèn)為我們必須充分關(guān)注這一問題。另一方面，旅游業(yè)已經(jīng)對我們生存的環(huán)境造成了巨大的壓力。水受到污染，生態(tài)平衡遭到破壞，自然資源被過度開發(fā)。

毫無疑問，由于在其他收入很少的地區(qū)，旅游業(yè)確實(shí)有助于發(fā)展經(jīng)濟(jì)，因此任何國家都無法禁止旅游業(yè)。重要的是旅游業(yè)毫無節(jié)制的發(fā)展可能使得經(jīng)濟(jì)發(fā)展不可持續(xù)。通過考慮環(huán)境保護(hù)因素，我們早就該提高人們的意識(shí)來扭轉(zhuǎn)這個(gè)現(xiàn)象了。

2010 Part B Directions:

Write an essay of 160-200 words based on the following drawing.In your essay, you should

1)describe the drawing briefly，2)explain its intended meaning, and then

3)give your comments.You should write neatly on ANSHWER SHEET 2.(20 points)文化“火鍋”：既美味又營養(yǎng)

文字說明：佛、解構(gòu)、人本、功夫、畢昇、儒、禮、后現(xiàn)代、老舍、莎士比亞、愛因斯坦、道、仁、天鵝湖、啟蒙、京劇等

As is symbolically illustrated in the portrayal, there is a boiling hotpot containing various ingredients of multi-cultures.These pluralistic cultures can be categorized as celebrities home and abroad as Bi Sheng, Lao She, Shakespeare and Einstein, philosophical concepts as Buddhism, Taoism, Confucianism, benevolence, rite, humanism, enlightenment, post-modernism and deconstruction, as well as performing arts as Peking Opera, Kong fu and Swan Lake.We are informed that the culture “hotpot” is both delicious and nutritious.The purpose of the cartoonist is to show us that instead of being outdated and of little value in a rapidly modernizing world, cultural blending should be encouraged and maintained.On the one hand, mosaic cultures are part of the universal heritage of humanity and they are powerful means of bringing together diverse peoples and social groups.Consequently, cultural reintegration has become indispensable as a means of promoting further culture development and maintenance.On the other hand, for China, as for any other rapidly developing country, there is a danger that age-old customs and traditions may become lost in the shadows of modernization.If kung-fu, Peking Opera or swan lake ballet ever perished from the earth, it would be a tragedy of immeasurable proportions.In my view, multi-cultures can be kept alive by the people with the time to do so, and is extremely vital in ensuring a community’s future development and prosperity.As a consequence of successful commercialization efforts, unwavering government support and growing interest overseas, the future of cultural blending looks brighter and more secure than ever before.如圖象征性所示，一只沸騰的火鍋中擁有諸多多元文化元素。這些多元文化可分為畢昇、老舍、莎士比亞、愛因斯坦等國內(nèi)外名人，佛、道、儒、仁、禮、啟蒙、人本、后現(xiàn)代、解構(gòu)等哲學(xué)概念，以及京劇、功夫、天鵝湖等表演藝術(shù)。文字說明顯示：“文化‘火鍋’，既美味又營養(yǎng)。”

畫家的目的是告訴我們文化融合并未過時(shí)或失去價(jià)值，相反還應(yīng)鼓勵(lì)和保持。一方面，多元文化作為全體人類遺產(chǎn)的一部分，是將不同人群和社會(huì)群體融合的有力方式。因此，文化融合作為促進(jìn)文化發(fā)展和保護(hù)的一種方式，已經(jīng)不可或缺。另一方面，中國跟世界上其他快速發(fā)展的國家一樣，年久的習(xí)俗和傳統(tǒng)面臨著消失在現(xiàn)代化陰影里的危險(xiǎn)。如果京劇、功夫或天鵝湖從地球上消失，那將是不可估量的悲劇。

在我看來，如果人們能為多元文化花費(fèi)時(shí)間的話，那么它就能得以保護(hù)。這對確保社會(huì)將來的繁榮和發(fā)展都至關(guān)重要。由于成功的商業(yè)努力、政府堅(jiān)定不移的支持和不斷增長的海外興趣，多元文化的將來會(huì)比過去任何時(shí)候更明朗、更安全。Part A Directions:

You are supposed to write for the postgraduate association a notice to recruit volunteers for an international conference on globalization.The notice should include the basic qualification for applicants and the other information which you think is relevant.You should write about 100 words on ANSWER SHEET 2.Do not sign your own name at the end of the notice.Use “ postgraduate association ” instead.(10 points)

Volunteers Needed

January 9, 2010 To improve students’ability and enrich extracurricular activities, the Postgraduate’Association is recruiting volunteers for an international conference on globalization to be held on April 7, 2010 in Beijing.To begin with, applicants should have Chinese nationality, a strong professional spirit, cheerful personality and be aged under 35.In addition, candidates must have outstanding skills at English listening comprehension and the ability to speak Chinese and English fluently.Finally, students with relevant professional experience are preferred.Those postgraduates who are interested in taking part in it may sign up with the monitor of their classes before February 1, 2010.Everybody is welcome to join in it.Postgraduate Association 參考譯文

招募志愿者

2010年1月9日

為提高同學(xué)們的能力并豐富課外活動(dòng)，研究生會(huì)現(xiàn)招募2010年4月7日在北京舉辦的一次國際全球化會(huì)議的志愿者。首先，應(yīng)聘者必須具有中國國籍、較強(qiáng)的職業(yè)精神、令人愉快的個(gè)性，年齡在35歲以下。其次，申請人需具有卓越的英文聽力水平以及流利的中英文演講能力。最后，具有相關(guān)職業(yè)經(jīng)驗(yàn)的學(xué)生優(yōu)先考慮。有興趣參加的研究生請于2月1日之前在本班班長處報(bào)名。歡迎大家積極參加。

研究生會(huì) 2008 Part B: Directions: Write an essay of 160-200 words based on the following drawing.In your essay, you should 1)describe the drawing briefly, 2)explain its intended meaning, and then 3)give your comments.You should write neatly on Answer Sheet 2.（圖略）

文字說明：“你一條腿，我一條腿；你我一起，走南闖北。”

As is symbolically illustrated in the cartoon, supporting each other with their powerful hands, two handicapped adolescents are continuing their new journey on the ground.Crutches left behind, they have successfully cracked the hard nut of lameness which might have confused the majority of the disabled.The caption indicates, “You have merely one leg and so do I.Helping each other, we can travel all around.”

Undoubtedly, we can deduce from the portrayal that the cartoonist is trying to attract our attention to the issue of cooperation.According to a survey conducted among a group of people who were in the same college class 10 years ago, those who are ready to give their cooperation to others all become rich or managers of all field, while not a single young man having difficulty in getting along with their classmates becomes an executive or boss.Why those who are excellent in team work tend to be managers or own their own enterprise in their later life? The answer seems self-evident.On the one hand, if you are competent in profession, but have difficulty in getting along with your colleagues and even your boss, you can hardly survive the corporation.On the other hand, your chances of success are much higher with wide circle of friends who are willing to cooperate with you to provide information and resources.It is my view that, first of all, we can frequently use the drawings to enlighten the juvenile to learn to cooperate successfully with each other.On the other hand, whatever difficulty or situation we are confronted with, those who have the spirit of cooperation and team work are nearer to success.Just as John Adams, the second U.S.president quoted from the ancient Greek Aesop’s Fables, “United we stand, divided we fall.”

2009 Directions: Write an essay of 160-200 words based on the following drawing.In your essay, you should 1)describe the drawing briefly, 2)explain its intended meaning, and then 3)give your comments.You should write neatly on Answer Sheet 2.As is symbolically illustrated in the portrayal, the Internet is a spider web of thousands of networks, linking schools, universities, businesses, government agencies, libraries and millions of individuals.Undoubtedly, the Internet exerts such a profound effect on our life that it revolutionizes the way of people’s living and thinking.The exaggerative and impressive cartoon has subtly revealed the duality of the relationship between man and Internet.On the one hand, something like information superhighways, the Internet can bring many conveniences into the school, home and office.With a basic computer and modem, any individual can call up information about almost anything from almost anywhere and anytime.But on the other hand, a great many people admit that they are too much addicted to Internet to maintain a regular and wholesome lifestyle.Such a waste of time inevitably leads to their failure in their life and work.Hence, it is necessary for us to use Internet in a reasonable way and restrain from overindulgence.For one thing, in addition to providing us many of the facilities and services we now must travel to obtain, with the Internet, the computer will even let us communicate directly with other homes and with information sources worldwide.For another, as nearly all activities could be conducted in the comfort of our homes, we could all become hermit-like, never feeling any need to leave the computer.Accordingly, the challenge of the Internet means we should consider how we can use it, so that it won’t control us.Part A: Directions: Restrictions on the use of plastic bags have not been so successful in some regions.“White Pollution”is still going on.Write a letter to the editor(s)of your newspaper to 1)give your opinions briefly, and 2)make two or three suggestions.You should write about 100 words.Do not sign your own name at the end of the letter.Use “Li Ming”instead.You do not need to write the address.Dear Editors, I have been reading your newspaper for many years with a great enthusiasm and interest.It is my view that limiting the use of disposable plastic bags is of utmost significance.To crack this hard nut, I would like to propose several practical recommendations as follows.First and foremost, it is imperative for us to ban the free use of disposable plastic bags.In addition, we should develop possible alternative forms to replace them, such as paper or clothing bags.Last but not least, plastic bags should be offered in a much higher price in department stores or supermarkets.I hope you will find the above proposals conducive and I would like to discuss this matter to further details.Your prompt attention to my suggestions would be highly appreciated.Yours sincerely, Li Ming

第四篇：《比較大小》教案

100以內(nèi)數(shù)的大小比較

望珺乙

教學(xué)內(nèi)容

人教版小學(xué)數(shù)學(xué)教材一年級(jí)下冊第42頁。教學(xué)目標(biāo)

1．知識(shí)與技能：使學(xué)生學(xué)會(huì)比較100以內(nèi)數(shù)的大小，并體會(huì)比較兩數(shù)大小的方法。

2．過程與方法：培養(yǎng)學(xué)生觀察、比較、提出問題和解決問題的能力。3．情感、態(tài)度與價(jià)值觀：利用現(xiàn)實(shí)有趣的情境激發(fā)學(xué)生的求知欲、學(xué)習(xí)數(shù)學(xué)的興趣。

重點(diǎn)難點(diǎn)

重點(diǎn)：掌握比較100以內(nèi)數(shù)的大小的方法。難點(diǎn)：正確比較100以內(nèi)數(shù)的大小。教具學(xué)具 教具準(zhǔn)備：課件。學(xué)具準(zhǔn)備：數(shù)字卡片。教學(xué)設(shè)計(jì)

一、創(chuàng)設(shè)情境，導(dǎo)入新課

1．談話：小朋友們，森林王國這幾天可熱鬧了，大家都爭先恐后地要報(bào)名參加數(shù)學(xué)夏令營活動(dòng)，想加入嗎？

可名額有限，人數(shù)又太多，怎么辦？于是，聰明的小猴提出：只要你能回答我的三道問題，闖過三關(guān)，就有機(jī)會(huì)去夏令營，誰愿意做勇敢的闖關(guān)者？

2.出示：

第一關(guān)：42里面有()個(gè)十和()個(gè)一。

從右邊起，第一位是()位，第二位是()位，第三位是()位。9是()位數(shù)，100是()位數(shù)，23是()位數(shù)。指名學(xué)生回答。

第二關(guān)：填上適當(dāng)?shù)姆?hào)（＞或＜）o 10○7 15○18

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集體用手勢表示后指名兩人說說，你是怎樣比較的。第三關(guān)：請數(shù)出37后面的5個(gè)數(shù)。同桌相互數(shù)數(shù)。

3．談話：祝賀小朋友們，你們闖關(guān)成功了，現(xiàn)在就可以順利參加夏令營了。

二、自主探索，靈活比較

1．出示課件（小松鼠和小兔正在海邊拾貝殼，小松鼠拾了37個(gè)，小兔拾了42個(gè)）。

(1)談話：瞧，小松鼠和小兔正在海邊拾貝殼呢，你還看到了什么？ 看著這幅圖你想知道什么？小松鼠和小兔比，誰拾得多呢？ 你會(huì)比較嗎？(2)合作交流。

談話：請把你的想法先說給小組同學(xué)聽一聽（小組內(nèi)交流）?？赡芮闆r：

a．我用數(shù)數(shù)的方法，42在37的后面，所以42比37多。b．四十幾個(gè)比三十幾個(gè)多，所以42比37多。

c．42的十位上是4，37的十位上3，4大于3，所以42比37多。誰愿意把你的想法說給大家聽一聽（在班內(nèi)充分交流）。(3)談話。

在這道題里比較哪一個(gè)小動(dòng)物拾的貝殼多就是比較37與42哪一個(gè)數(shù)大。你能用一個(gè)數(shù)學(xué)符號(hào)表示它們之間的大小關(guān)系嗎？

教師板書：42 37 指定學(xué)生板演：＞

全班學(xué)生讀一讀算式：42＞37。(4)提問。

誰能起來再和大家說說你是怎樣比較它們的大小。（多指名學(xué)生充分說一說）2．出示課件。

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(1)談話：參加夏令營的小伙伴人人都想取得好成績，想比比自己的能力，于是他們請來了珠算先生當(dāng)裁判，出難題考考大家。你能寫出計(jì)數(shù)器上表示的數(shù)并比較它們的大小嗎？

學(xué)生自己填寫。

交流時(shí)要求學(xué)生說出比較的方法。(2)指名學(xué)生板演：23<＼25 0 追問：這時(shí)候，你又是怎么比較的？ 多指名學(xué)生充分說說自己的比較的方法。(3)完成“做一做”的第1題。

談話：再來挑戰(zhàn)一次，比一比這次誰的能力更強(qiáng)。集體交流，說說你的比較方法是什么。

三、實(shí)際應(yīng)用，形成內(nèi)需 談話：比一比誰的反應(yīng)最快。

1．搶答游戲：填上“＞”或“＜”（“做一做”的第2題）。請你用相應(yīng)的手勢快速表示。交流，說說自己的比較方法。2．寫數(shù)游戲。

(1)下面我們再來動(dòng)動(dòng)小手，寫出三個(gè)個(gè)位上都是6的兩位數(shù)。學(xué)生寫好后教師提問：你寫了哪三個(gè)數(shù)？誰最大？誰最??？ 你能把這三個(gè)數(shù)按一定的順序排列嗎？（這個(gè)學(xué)生在黑板上排，其余學(xué)生在座位上排）為什么這樣排？（可以從小到大，也可以從大到小排）個(gè)位上是6的兩位數(shù)有幾個(gè)？（順次說一說）

(2)寫出三個(gè)十位上都是6的兩位數(shù)，比一比哪個(gè)最大，哪個(gè)最小。讓學(xué)生都獨(dú)立完成后再相互交流。

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四、課堂總結(jié)

提問：通過參加這次數(shù)學(xué)夏令營活動(dòng)，你學(xué)到了什么數(shù)學(xué)知識(shí)？（揭示板書課題：100以內(nèi)數(shù)的大?。?/p>

學(xué)會(huì)了什么本領(lǐng)，能和小朋友說說你的體會(huì)嗎？（學(xué)生說說自己的體會(huì)）板書設(shè)計(jì)

教學(xué)反思

100以內(nèi)數(shù)的大小比較這節(jié)課，是在學(xué)習(xí)100以內(nèi)數(shù)的認(rèn)識(shí)和順序以及20以內(nèi)數(shù)的大小比較的基礎(chǔ)上學(xué)習(xí)的。100以內(nèi)數(shù)的大小比較是小學(xué)階段整數(shù)大小比較的基礎(chǔ)和重點(diǎn)?，F(xiàn)對本節(jié)課，反思如下：

一、創(chuàng)設(shè)情境，讓學(xué)生體會(huì)數(shù)學(xué)的趣味性和實(shí)用性

本節(jié)課對教材進(jìn)行了合理的開發(fā)與整合，構(gòu)建了幾個(gè)大活動(dòng)板塊，添加了一些活動(dòng)素材，如創(chuàng)設(shè)故事情節(jié)——“拾貝殼比賽”，使學(xué)習(xí)素材富有現(xiàn)實(shí)意義，更具趣味性和挑戰(zhàn)性，不僅充分調(diào)動(dòng)了學(xué)生學(xué)習(xí)的主動(dòng)性和積極性，也豐富并促進(jìn)了他們學(xué)習(xí)情趣的養(yǎng)成。

二、在學(xué)習(xí)知識(shí)的同時(shí)注意思想方法的滲透

本節(jié)課注重為學(xué)生創(chuàng)設(shè)一些開放的問題情境，如“你是怎樣比較42與37的大小的？”，“你是怎樣想的？”等，而且注重為學(xué)生提供開放的探索空間，讓學(xué)生能充分地進(jìn)行獨(dú)立思考、探討交流等，在這種開放的學(xué)習(xí)過程中，使學(xué)生能積極去探尋解決問題的策略，主動(dòng)去交流自己解決問題時(shí)的思維過程，充分去感受比較策略的多樣化，增強(qiáng)了學(xué)生的自主意識(shí)，逐步加深學(xué)生對數(shù)學(xué)學(xué)習(xí)的認(rèn)識(shí)和理解。

三、尊重學(xué)生，兼顧學(xué)習(xí)活動(dòng)的有效性和發(fā)展性

本節(jié)課充分尊重學(xué)生的生活經(jīng)驗(yàn)，充分尊重學(xué)生的選擇，使他們在借助計(jì)數(shù)器比較的過程中經(jīng)歷了數(shù)學(xué)化的過程，有效地進(jìn)行了比較方法的優(yōu)化；充分尊重學(xué)生的理解，使他們在學(xué)習(xí)活動(dòng)中不斷感受到比較的現(xiàn)實(shí)意義和價(jià)值，而且充分尊重學(xué)生，也使得學(xué)生在有效的學(xué)習(xí)活動(dòng)中，知識(shí)體驗(yàn)和情感體驗(yàn)不斷得以豐富和提升，真正促進(jìn)了他們的持續(xù)發(fā)展。

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第五篇：識(shí)字《大小》

識(shí)字《大小》教學(xué)設(shè)計(jì)

廣安市特殊教育學(xué)校

彭曉燕

教學(xué)目標(biāo)：

1、2、學(xué)生能初步比較兩個(gè)物品的大小，理解大小的含義。學(xué)生能認(rèn)讀生字“大、小”。

3、能在生活中認(rèn)讀大小，提高學(xué)生的生活識(shí)字能力。

4、培養(yǎng)學(xué)生觀察能力，激發(fā)學(xué)生識(shí)字的興趣。A生：（程科銘、左青龍、李鳳林）能初步比較兩個(gè)物品的大小

能認(rèn)讀生字“大小”，理解大小的含義。能在生活中認(rèn)讀大小，培養(yǎng)學(xué)生的識(shí)字能力。培養(yǎng)學(xué)生的觀察能力，激發(fā)識(shí)字的興趣。B生：（周尚慧、辛大潤、鄧雨）能初步比較兩個(gè)物品的大小。

能看圖認(rèn)讀生字“大小”，在老師設(shè)定的環(huán)境中理解大小的含義。能激發(fā)學(xué)生的識(shí)字興趣，提高學(xué)生的識(shí)字能力。C生：（曾朝誠、周欣、康欣雨、向雨涵）能參與課堂活動(dòng) 能跟讀生字“大小”。

能在老師設(shè)定的環(huán)境中，理解大小的含義。教學(xué)重點(diǎn)：

能認(rèn)讀生字“大、小”，理解大小的含義。教學(xué)難點(diǎn)：

1、能認(rèn)讀生字“大、小”，理解大小的含義。

2、能在生活中認(rèn)讀大小，提高學(xué)生的生活識(shí)字能力。

教學(xué)準(zhǔn)備:ppt、實(shí)物大小不用的兩個(gè)蘋果、生字卡、圖片（大門、小門、大床、小床、大碗、小碗）教學(xué)過程

一、創(chuàng)設(shè)情境，激發(fā)興趣

1、師：同學(xué)們看看今天哪個(gè)卡通人物來到了我們的課堂？ 生：熊大熊二

2、解決問題

師：熊大熊二遇到了一個(gè)難題，你們愿意幫助他們嗎？（生：愿意）這里有兩個(gè)蘋果，熊大想吃大蘋果？你能幫他找到這兩個(gè)蘋果中哪個(gè)是大蘋果嗎？熊二想吃小蘋果，誰來幫幫他？找到哪個(gè)是小蘋果？

注：PPT同時(shí)出示（大蘋果）（小蘋果）

3、熊大熊二想和同學(xué)們一起來學(xué)習(xí)認(rèn)識(shí)“大小”，以后他們就可以自己解決這樣的難題了。出示課題：識(shí)字《大小》

二、探究新知

1、認(rèn)讀生字“大小”

師：剛才同學(xué)們知道了，這是大蘋果，那你們知道這個(gè)字怎么讀嗎？教師拿出大的生字卡讓學(xué)生認(rèn)讀 教師范讀，教生讀（讓學(xué)生舉起自己字卡中的大字）,開小火車讀

師：同學(xué)們和熊大熊二一起學(xué)習(xí)了大這個(gè)生字，知道了大蘋果的大，小蘋果的小呢？他又長什么樣子呢？ 師：拿出“小”字卡，和學(xué)生一齊認(rèn)讀

教師范讀，教生讀（讓學(xué)生舉起自己手中字卡中的小字），開小火車讀

2、通過看圖比較認(rèn)讀

熊大熊二為了感謝同學(xué)們幫他們找到自己想要的蘋果，還和小朋友們一起高興的學(xué)習(xí)了認(rèn)識(shí)大小兩個(gè)字。他們想請小朋友們到他家去做客，你們想去嗎？好那我們現(xiàn)在就出發(fā)。

來到熊大熊二的家，你們看到了什么？師：出示圖片，請學(xué)生觀察兩扇門有什么不一樣？

門（大門、小門），一齊看圖說一說抽B、C生來指認(rèn)圖片，A生將自己手中對應(yīng)的大小字卡貼在大門和小門的旁邊。走進(jìn)門，我們看到兩張床，一齊看圖說一說哪張是大床，哪張是小床？抽B、C生來指認(rèn)圖片，A生將自己手中對應(yīng)的大小字卡貼在大床和小床旁邊。

我們再看看廚房有什么？兩個(gè)碗，哪個(gè)是大碗，哪個(gè)是小碗？抽B、C生來指認(rèn)圖片，A生將自己手中對應(yīng)的大小字卡貼在大碗和小碗旁邊。

三、拓展練習(xí)，回歸生活

1、在生活中，找到我們今天學(xué)過的“大小”。

好了，小朋友們剛才參觀了熊大熊二的家，現(xiàn)在熊大熊二帶我們到他家附近去看看，你們還能找到“大、小”兩個(gè)字嗎？如果你們能找到一會(huì)熊大熊二會(huì)拿好吃的款待大家。

師：PPT出示圖片，抽生來找到各種標(biāo)牌，與實(shí)物上的大小兩個(gè)字，帶領(lǐng)其他同學(xué)讀一讀。

3、小朋友，用你們的火眼金金再去找找我們生活中還有哪些地方能見到大小兩個(gè)字，把他告訴自己的爸爸媽媽。

四、總結(jié)

1、今天熊大熊二歡迎你們到他家來做客，給同學(xué)們帶來了美味的食物，你們想吃嗎？那你能找到這個(gè)食物上有我們今天學(xué)過的小字嗎？師：分發(fā)食物，逐個(gè)指導(dǎo)學(xué)生找到法式小面包中的”小”字。

五、板書設(shè)計(jì)

識(shí)字《大小》