第一篇:三年级英语 阅读理解天天练 美国孩子学中文(含解析)
美国孩子学中文
同学们现在都在努力学英文,大家知道吗?就在你们认真背ABC的同时,大洋彼岸的小伙伴们也在努力学习中文呢„本文适合小学三年级学生阅读练习。
You work hard to learn English.Do you know American kids are learning Chinese? In many US schools, students take Chinese lessons.How do they learn Chinese? Let’s go to the Muir Elementary School in the US.Maddi, 6, and Stephen, 6, are first graders in this school.They are learning how to say “we” in Chinese.“It’s not easy to remember the Chinese characters(汉字).But learning Chinese is fun,” they say.In Chinese class, they are learning the language through songs, games and lots of talking.“Chinese is popular among US kids.They pick it up really fast,” their teacher says.【小练习】判断下面句子正确与否,正确的写“T”,错误的写“F”。
1.()We work hard to learn English and the US kids work hard to learn Chinese.2.()Students in US schools never learn Chinese lessons.3.()In the Muir Elementary School in the US, Maddi and Stephen are learning how to say “we” in Chinese.4.()To US kids, it's not easy to remember the Chinese characters.5.()In Chinese class, US kids are learning the language through songs, games and lots of listening.【解析】
1.T.从文章第一段可以知道“中国孩子努力学英语的同时,美国孩子们也在学中文呢。”,所以这题是正确的。
2.F.从文章第一段第三句In many US schools, students take Chinese lessons.“在许多美国学校,孩子们会上中文课。”可以知道题目中说“他们从不上中文课”肯定是不对的啦。注意这里never是“从来不”的意思噢。
3.T.从文章第二段可以知道在美国的Muir小学,Maddi和Stephen正在学习怎么用中文说“我们”,所以这题是正确的。
4.T.从文章第二段后半部分可以知道“对于这些美国孩子来说,学习汉字可不简单噢!”,所以这题也是正确哒~
5.F.从文章最后一段第一句In Chinese class, they are learning the language through songs, games and lots of talking.“在美国的中文课上,当地孩子们通过歌曲,游戏和谈话的方式来学习中文。”可是题目中把“谈话”变成了“听力”,所以很可惜,这题是不正确哒!
第二篇:三年级英语 阅读理解天天练《熊猫总动员》(含解析)
《熊猫总动员》
Pandy是只可爱的小熊猫,他是个男孩噢!Pandy和他的家人、朋友们快乐地生活在森林里。每天大家一起玩耍、一起成长,可是突然有一天„快来看故事并完成小练习吧。本文适合小学三年级学生阅读练习。Pandy is a lovely panda.He lives happily with his family and friends in the forest.One day, some terrible enemies(敌人)come.The pandas are in danger(处在危险中).Pandy wants to save his friends and family, but he doesn’t know kungfu.How will he fight the enemies?
You can watch the 3D cartoon movie, Little Big Panda(《熊猫总动员》)and find the answer.China and Europe made this film together.【练习1】判断下面句子正确与否,正确的写“T”,错误的写“F”。
1.()Little Big Panda is a film.It's Chinese name is “熊猫总动员”.2.()The film is made by the United States.3.()Pandy is the name of a lovely boy panda and he lives happily in the forest.【解析】
1.T.从文章最后一段You can watch the 3D cartoon movie, Little Big Panda(《熊猫总动员》)and find the answer.可以知道这的确是部电影,而且如果同学们平时关系电影的话,应该也会略有耳闻吧!
2.F.从文章最后一句China and Europe made this film together.可以知道这部电影是“中国和欧洲联合打造”哒!所以不是美国打造的噢!
3.T.从文章前两句Pandy is a lovely panda.He lives happily with his family and friends in the forest.“Pandy是只可爱的熊猫。他和家人、朋友们快乐地住在森林里。”可以知道Pandy是个男熊猫宝宝噢,因为文中用了he嘛,而且他确实快乐地生活在森林里呢!
第三篇:高一英语天天练
洪翔中学2013~2014学年高一英语午练试卷(七)
满分60时间50分钟使用时间:2013.12.12
I.Multiple choice(1×15=15分)
1.As far as I see, ___ is no possibility ___ he will win the tennis match.A.it;thatB.there;thatC.it;whetherD.there;whether
2.In the factory women ___44% of the workforce(劳动力), and nearly half the mothers with children are in paid work.A.make upB.set upC.build upD.take up
3.— Was there lots of fun at yesterday’s party?
— Yes.We all enjoyed ourselves.You ___ have come, but why didn’t you come?
A.mustB.shouldC.mightD.need
4.My friend persuaded me to take an umbrella with me on the holidays ______rain.A.in case ofB.in want ofC.as a result ofD.in spite of
5.I’d like to arrive 20 minutes early ____ I can have time for a cup of tea.A.as soon asB.as a resultC.in caseD.so that
6.Every possible means ____ to prevent the air pollution, but the sky is still not clear.A.is usedB.are usedC.has been usedD.have been used
7.——I bought ___ eggs, Mom.——Did you? There are still ___ eggs in the fridge!
A.two dozens;dozens ofB.two dozen;dozens of
C.two dozen;dozen ofD.two dozens;dozen of
8.In front of the temple ___ two tall trees, which ___ said to de over eight hundred years old.A.are;areB.is;isC.are;isD.is;are
9.Mr.Smith is so busy ______ his office work that he spends little time ______ after
his children.A.in;lookingB.with;to lookC.with;lookingD.in;to look
10.I’ll tell you ______ I see in my new neighborhood the moment I settle down there.A.whateverB.wheneverC.HoweverD.wherever
11.Enough sleep can make us ________ energy and make it possible for us to perform well in the exam.A.filled ofB.full ofC.fill withD.full with
12.The country life he was used to _____ greatly since 1992.A.changeB.has changedC.changingD.have changed
13.What’s the way you think of ____ your handwriting?
A.to improveB.improvingC.how to improveD.for you improve
14.Give them a hand this time and I am sure they will offer theirs______ in the future.A.by turnsB.in turnC.at turnD.in return
15.We insisted that he ______ badly ill and that he _____ to hospital at once.A.was;was sentB.was;be sent
C.should be;should be sentD.be;was sent
II.Cloze(1×20=20分)
As soon as I learned to say the word “beauty”, I set out to look for it.Before I
could find it, I asked my mother what a beauty was like.She said that a beauty iswho has large bright eyes and fine skin.When I was in Grade Four, I such a girl.I sat right in front of her andher to see if she was a real beauty.She a beauty in my eyes until the day sheher pencil box which I knocked on to the floor.I Suddenly she flew at me and threw me onto the ground and we rolled abouteach other.During the years that followed, I came acrossexplanations given to me by different people.Some said a girl with a thin figure(体形)is a beauty, that a girl with a gentle voice is beautiful, said it is a girl with hair that is like a waterfall.I give these a second thought.I searched for a beauty had told me before, but it was useless.Then I met an old man.He told me that a beauty is a girl who might not be quitewith natural beauty.However, she becomes a beautyexperiencing hardship.After a 10-year hunt for a beauty, I found her.She became my family and had to take care of herself from young.When we married, I really got the idea about a beauty.She was the one the16.A.your classmateB.a girlC.an experienced girlD.an ugly girl
17.A.likedB.was tired ofC.was againstD.found
18.A.stared atB.scoldedC.beatD.laughed at
19.A wasn’tB.pretended to beC.treated himselfD.was
20.A.quarreledB.talkedC.playedD.studied
21.A.stealB.rob her ofC.likeD.pick up
22.A.by chanceB.by no meansC.by herselfD.by the way
23.A.agreedB.refusedC.was happyD.did so
24.A.talking withB.helpingC.hittingD.leaving
25.A.the sameB.differentC.the oppositeD.some correct
26.A.butB.orC.asD.so
27.A.EveryoneB.The othersC.NobodyD.Others
28.A.didB.mustC.didn’tD.should
29.A.an old manB.some peopleC.nobodyD.my mother
30.A.luckyB.sadC.willingD.happy
31.A.afterB.withoutC.likingD.against
32.A.friendB.teacherC.classmateD.girlfriend
33.A.uglyB.beautifulC.lovelyD.bright
34.A.richB.farmer’sC.happyD.poor
35.A.foolishB.kind-heartedC.wiseD.honest III.Reading Comprehension(2×8=16分)
A
Letter to Editor of TV Weekly
Dear Sir/Madam,I read Alison Burnham’s review of When we were 12, and I do not agree with her.I thought the programme was wonderful — I found the old news pictures really interesting — they helped to bring to life the stories the people were telling.The programme reminds me of many things from my own childhood.For example, one day when I was about five, I was going to school on the bus by myself(this was the late 1960s).My mother had given me exactly the right money for a return ticket.I held out my hand with the money in it — one big coin on top of one little coin.The bus conductor took the big top coin only and she gave me a ticket, but it was a pink one for a single journey.I needed a white one for a return journey, but I was too frightened to say anything.When school finished for the day, I couldn’t catch the bus home — I had to walk.As a grown-up, whenever I’ve been in a situation where I need to say something or take some action, this early memory of my bus ride comes back to me, and I’m able to take control of the situation.I would like to say to the director, Bret Chrysler, carry on making this kind of programme.Too much TV these days is quiz shows and so called “reality programmes”.I appreciate the human story that can make me laugh and cry.Yours faithfully,Chris Daniels
36.What is Chris Daniels’ purpose of writing this letter?
A.To persuade Bret Chrysler to turn away from quiz shows.B.To entertain other readers with old news pictures.C.To express his appreciation of the programme.D.To have his story told on the programme.A.describe how painful his early experience was
B.draw a direct response from Alison Burnham
C.show how the programme made him think
D.teach the readers of TV Weekly a lesson
A.he hadn’t got a return ticketB.he had lost his bus ticket
C.he didn’t like big crowdsD.he missed the bus home
39.What does Chris Daniels now think about his experience on the bus?
A.He should have told the conductor then.B.He should have been well treated.C.He regrets going to school alone.D.He wishes it hadn’t happened.B
Several interesting American museums tell about health subjects.One is the Doctor Samuel D.Harris National Museum of Dentistry.It is at the University of Maryland in Baltimore.That is where the first college in the world to train dentists began.The museum tells about the history of the medical treatment of teeth.Visitors 受感染的)teeth.They also can see sets of teeth made of animal bone.They were made for a
famous American--the first President, George Washington.Most people do not consider a visit to the dentist their idea of a good time.However, the director of the museum says he wanted to make the museum a fun place to visit.He says he also wants to teach visitors about the importance of taking care of their teeth.Hearing Aid Museum is at Kent State University in Kent, Ohio.The museum has more than three-thousand hearing aids from around the world.They include old and strange devices.Some hearing aids were made to look like other objects.That is because in the past many people did not want anyone to know they were wearing a hearing aid.40.It is common for people to think it uneasy to pay a visit to ____.A.the University of MarylandB.the Museum of Dentistry
C.the Hearing Aid MuseumD.the dentist
41.The text mainly tells about _____.A.museums in the US
B.interesting American museums
C.American museums with health subjects
D.the history of the medical treatment of teeth
42.What do we learn about George Washington from the text?
A.He once visited the National Museum of Dentistry.B.He considered the Museum of Dentistry a fun place to visit
C.His artificial teeth were collected in the National Museum of Dentistry.D.His teeth seemed to be made of animal bone.43.The underlined word “devices” in the first and last paragraph probably means _____.A.meansB.strategiesC.toolsD.desires
Ⅳ.Complete sentences according to the initials or Chinese.(1.5×6=9分)
44.The boy watched the plane until it ____________(消失)from view.45.The local newspaper made ________________(安排)for an interview with Professor Li.46.I didn’t see your car, so I _____________(认为)you’d gone out.47.The spokesman said that many strange customs had _________(存在)from earlier times.48.There is no a_______________ words to express my thanks to my parents.49.Lynne, a friendly person with a great sense of h__________, can make the whole audience laugh.
第四篇:二年级英语 阅读理解天天练 小屁孩日记(含解析)
小屁孩日记
小屁孩日记
Greg Heffley is an 11-year-old boy.He is kind, honest, smart and naughty.He has a lot of ideas.He has a diary.In his diary, he writes many interesting stories about his life.He also draws cartoons in his diary.He has a lot of problems in school.But he makes a lot of trouble, too.He runs away from a school singing contest(比赛).He often wants to play tricks(捉弄)on others.But he always makes a fool of himself(出洋相).He is not good at making friends.But he wants to be the most popular in his school.Greg is not a good role model(榜样).But US children like reading his diaries.In fact(实际上), everything Greg does, you should do the opposite(相反).Do you want to read about him?Go and read the book, Diary of a Wimpy Kid(《小屁孩日记》).It won the Favorite Book award(奖项)at the 2010 Kids’ Choice Awards in the US.【小练习】判断下面句子正确与否,正确的写“T”,错误的写“F”。
1.()Greg Heffley is an 11-year-old boy.2.()Greg Heffley has no idea,but he has a diary.3.()In his diary, he writes many interesting stories about his life.4.()He runs away from a school dancing contest(比赛).5.()Greg is not a good role model(榜样).【解析】
1.T.从文章第一句Greg Heffley is an 11-year-old boy.可以知道这句话是正确的。
2.F.从文章第三、第四句He has a lot of ideas.He has a diary.“Greg有很多鬼点子。他还有本日记。”可以知道题目中说“他没有鬼点子”是不对的啦。
3.T.从文章第五句In his diary, he writes many interesting stories about his life.“在日记里,他写了好多生活中有趣儿的故事。”可以知道这题是正确的。
4.F.从文章第九句He runs away from a school singing contest(比赛).“他从学校唱歌比赛中逃出来了。”可以知道题目中说的“舞蹈比赛”是错误的啦。
5.T.从文章第二段第一句Greg is not a good role model(榜样).“Greg可不是个好榜样。”可以知道这题是正确滴。想想也是啊,他老是捣乱、出状况,我们可不能学习他噢!
第五篇:三年级奥数天天练
三年级奥数天天练
1、小华在计算一道题时,把一个数加上4乘2看作了乘2加上4,得数为40。正确的得数是多少?
2、小红在计算有余数除法时,把被除数113错写成131,这样商比原来多2,但余数恰好相同。正确的除数和余数是多少?
3、小华、小林、小黄三人期末考试数学成绩总和为289分,已知小华比小林多8分。小林比小黄少8分,三个人各得多少分?
【答案】可以知道小华和小黄的分数相同,均比小林多8分,因此小华和小黄的分数为(289+8)÷3=99(分),所以小华的人数为91分。
4、两个数的和是2016,其中一个加数的个位是0,如果把这个0去掉,就正好等于另一个加数的两倍。这两个加数各是多少?
【答案】因为把第一个加数个位上的“0”去掉,得到了第二个加数的2倍,所以,第一个加数是第二个加数的20倍.把第二个加数看作“1倍数”,第二个加数就是“20倍数”,这两个数的和2016就是“1+20”倍的数.根据这个“量”与“倍”的对应关系,可先求出第二个加数.这两个加数分别是: 2010÷(1+20)=96,2016-96=1920 5、6、10、14、18、„„最后一项是86,问数列共有几项? 【答案】这是一个以6为首项,4为公差的等差数列,根据公式,86=6+(n-1)×4,所以n=21,即这个数列共有21项。6、100与500之间能被9整除的所有自然数之和? 【答案】第一个能被9整出的数是108,最后一个是495,共(495-108)÷9+1=44项,所以100与500之间能被9整除的所有自然数之和为。
7、今年小玲8岁,她父亲36岁,当两人年龄和是62岁时,两人年龄各多少岁? 【答案】在年龄问题中必须记住两人的年龄差不变这个解题关键。题中没有给出小玲和父亲的年龄之差,但是已知两人今年的年龄,那么两人的年龄差是34-6=28(岁),不论再过多少年,两人的年龄差是保持不变的,所以当两人年龄和为58岁时,他们的年龄差仍是28岁,根据和差问题就可解此题。
父亲的年龄:[62+(36-8)]÷2=〔62+28〕÷2=90÷2=45(岁)
小玲的年龄:62-45=17(岁)
答:当两人年龄和为62岁时,父亲的年龄是45岁,小玲的年龄是17岁。
小结:解这类题的关键是理解两人的年龄差是固定不变的,即两人的年龄是同时增长的。
8、小华今年12岁,他妈妈今年48岁,多少年以前妈妈的年龄是小华的5倍? 【答案】小华和他妈妈年龄的差都是不变的,妈妈的年龄比小华大48-12=36岁,根据差倍公小华当时的年龄为36÷(5-1)=9岁,所以是12-9=3年前。
9、鸡兔同笼,头共46,足共128,鸡兔各几只?
【答案】假设法,运用公式鸡数=(每只兔脚数×总头数-总脚数)÷(每只兔脚数-每只鸡脚数)、兔数=总头数-鸡数。
所以,鸡数=(4×6-128)÷(4-2)=(184-128)÷2=56÷2=28(只)
兔数=46-28=18(只)。
10、鸡与兔共有100只,鸡的脚比兔的脚多80只,问鸡和兔各多少只?
【答案】假设100只全是鸡,那么脚的总数是200只,这时兔脚是0只,鸡脚比兔脚多200只,二实际上鸡脚比兔脚多80只,因此,鸡脚与兔脚的差比实际多了200-80=120(只),这是因为把其中的兔换成了鸡,每把一只兔换成鸡,鸡脚就增加2只,兔脚就减少4只,鸡脚与兔脚的差数增加2+4=6(只),所以换成鸡的兔子有120÷6=20(只),有鸡100-20=80(只)。
11、马路的一边每相隔9米栽有一棵柳树。张军乘汽车5分钟共看到501棵树.问汽车每小时走多少千米?
【答案】张军5分钟看到501棵树意味着在马路的两端都植树了;只要求出这段路的长度就容易求出汽车速度。
5分钟汽车共走了:9×(501-1)=4500(米),汽车每分钟走:4500÷5=900(米),汽车每小时走:900×60=54000(米)=54(千米)
列综合式:9×(501-1)÷5×60÷1000=54(千米)
答:汽车每小时行54千米。
12、某人要到一座高层楼的第8层办事,不巧停电,电梯停开,如从1层走到4层需要48秒,请问以同样的速度走到八层,还需要多少秒?
【答案】要求还需要多少秒才能到达,必须先求出上一层楼梯需要几秒,还要知道从4楼走到8楼共走几层楼梯。上一层楼梯需要:48÷(4-1)=16(秒),从4楼走到8楼共走8-4=4(层)楼梯。到这里问题就可以解决了。
上一层楼梯需要:48÷(4-1)=16(秒)
从4楼走到8楼共走:8-4=4(层)楼梯
还需要的时间:16×4=64(秒)
答:还需要64秒才能到达8层。
13、如果a△b=(a-2)×b,例如3△4=(3-2)×4=4,当a△5=30时,那么a是多少呢?
14、对于数a、b、c、d规定<a,b,c,d>=2ab-c+d,如果<1,3,5,x>=7,那么x是多少?
15、有同样大小的红白黑珠共96个,按先5个红的,再4个白的,再3个黑的排列着,如图:◎ ◎ ◎ ◎ ◎ ○ ○ ○ ○ ● ● ● ◎ ◎ ◎ ◎ ◎ ○ ○ ○ ○ ● ● ● ◎ ◎ „试问:黑珠共的几个?
16、观察下面已给出的数表,并按规律填空:
5
9 11 15 17 19 23()27 29
33 35()39 41
17、昨天是9日,今天是星期三,29日是星期几? 【答案】昨天是9日,今天就是10日(星期三),再过1个星期、2个星期、3个星期都是星期三10日再过19天就是29日,所以,要看19天中有多少个7天,还余几天。
29-10=19(天)
19÷7=2„„ 5
星期三再过5天就是星期一,所以,29日是星期一。
18、小明1999年已经20多岁了,可是他1996年才过第6个真正的生日。问,小明出生在几月几日,1999年小明几岁(小明刚出生那天算做第1个生日)?
【答案】20多岁的人才说过了6次生日,说明他得生日(日期)不是每年都有,或者说他得生日几年才出现一次,这个日子很特殊,只能是闰年的2月29日。在1996年前,还有1992、1988、1984、1980、1976„„是闰年。因为小明1996年过第6个生日,说明他是在1976年出生的!
1996-4×(6-1)=1976
小明1999年的岁数是1999-1976=23(岁)。
19、将 2~9这八个数分别填入下图的○里,使每条边上的三个数之和都等于18。
【答案】四个角上的数是重叠数,重叠次数都是1次。所以四个重叠数之和等于18×4-(2+3+„+9)=28。而在已知的八个数中,四数之和为28的只有:4+7+8+9=28或5+6+8+9=28。又由于18-9-8=1,1不是已知的八个数之一,所以,8和 9只能填对角处。由此得到下图所示的重叠数的两种填法:
“试填”的结果,只有第三个图的填法符合题意。20、将1~8这八个数分别填入下图的○中,使两个大圆上的五个数之和都等于21。
【答案】中间两个数是重复数,重复次数都是1次,所以两个重叠数之和为21×2-(1+2+„+8)=6.在已知的八个数中,两个数之和为6的只有1+5或者2+4。每个大圆上另外三个数之和为21-6=15。
如果两个重叠数为1和5,那么剩下的六个数2、3、4、6、7、8平分为两组,每组三个数之和为15的只有2+6+7=15和3+4+8=15。
如果两个重叠数为2和4,同理可得到1+6+8=15和3+5+7=15。所以填法如下图 21、199 + 99 + 9= 【答案】用“凑整”的方法。199 + 99 + 9=(199 + 1 - 1)+(99 + 1 - 1)+(9 + 1 - 1)= 307 22、364-(476-187)+213-(324-236)-150= 【答案】“去括号”法则,用“凑整”的方法,带着符号搬家,“添括号”法则。
364-(476-187)+213-(324-236)-150
= 364-476+187+213-324+236-150
=(364+236)+(187+213)-(476+324)-150=600+400-800-150=50
23、海洋馆里有8只海象,总共运来170千克鱼给它们吃,前两天这8只海象共吃了80千克鱼,两天后把其中的2只海象运走。剩下的鱼还可以让余下的海象吃几天?
24、小强要清点盒子中的画片,他叫来小红帮忙,两人同时开始数。小强比小红动作快,小强数5张的时间小红只数3张,但小强数到第30张时忘了数到几,只好把数过的画片全部放回盒中,再从头开始数,当小强数到第120张时,盒子里恰好剩下2张画片。盒子里原来有多少张画片?
25、三堆糖果共有105颗,其中第一堆糖果的数量第二堆的3倍,而第三堆糖果的数量又比第二堆的2倍少3颗,第三堆糖果有多少颗?
【答案】学会画线段图表示数量关系
由图可得:第三堆等于(105+3)÷6×2-3=33颗
26、红旗小学三年级有甲、乙、丙三个班,一共有学生162人,如果从甲班转出2个人到乙班,则甲、乙两班人数相同。如果这时再从丙班转出3个人到乙班,则乙、丙两班人数相同。请问:甲班原来有多少人?
【答案】学会分析并画线段图表示数量关系
甲班转出2个人到乙班,则甲、乙两班人数相同,说明甲班比乙班多4人;
这时再从丙班转出3个人到乙班,则乙、丙两班人数相同,说明丙班比乙班多6+2=8人
由图可得:162÷3=54人
27、小悦、冬冬、阿奇三个人去看电影,他们买了三张座位相邻的票。他们三人的座位顺序一共有多少种不同的安排方法?
28、现在有1分、2分、5分的硬币各5枚,要用这些硬币凑出2角钱,一共有多少种不同的凑法?
29、如图7-11,伸出左手,估后从大拇指起开始数,当数到200的时候,正好数到哪根手指?
【答案】找准一个周期中的数,不要直接错误的人数周期数为5
通过观察分析,容易发现周期中的数为(1-2-3-4-5-6-7-8),然后9又开始从大拇指数起,进行了一个循环,一个周期有8个数,所以200÷8=25次,能够整除,故数到25个周期结束的时候恰好到了200,所以数到200时正好到了食指上。
30、如图7-13所示,7个小朋友围成一圈,沿顺时针方向依次编号为1-7。然后,按如下方法给他们发糖:先给1号小朋友1块糖;然后沿顺时针方向隔过一个人后,给3号小朋友1块糖;再沿顺时针方向隔过两个人后,给6号小朋友1块糖;接着又沿顺时针方向隔过一个人后,给1号小朋友1块糖„„如此反复地间隔一个人、两个人,直到1997块糖全部分完,那么最先发到糖的那位小朋友一共得到了多少块糖?
【答案】通过演练操作,找出一周期,确定一周期中的数以及各个小朋友一周期能分到的糖
通过操作,发现周期中的数是(1,3,6,1,4,6,2,4,7,2,5,7,3,5),所以一周期中1号小朋友被分到了2次,故有42块糖,然后由1997÷14=142(次)„„9,得出进行了142次周期以及第15周期中轮到了7号小朋友,所以1号小朋友拿到:142×2+2=286(块)。
31、如图8-7(a)所示,我们用8根火柴摆放成了一条向左游动的鱼,请移动3根火柴,使得这条鱼掉头向右游动;
32、如图8-17,黑板上画了9个点,我们可以用5条线段把它们串联起来,而且这5条线段是可以用一笔画成的,实际上我们可以做得更好:用4条线段就能把这9个点串联起来,而且这4条线段仍然是用一笔画成的。请大家找出这种画法。
33、今有雉兔同笼,上有三十五头,下有九十四足,问雉兔各几何?
【答案】题目中给出了鸡兔共有35只,如果把兔子的两只前脚用绳子捆起来,看作是一只脚,两只后脚也用绳子捆起来,看作是一只脚,那么,兔子就成了2只脚,即把兔子都先当作两只脚的鸡。鸡兔总的脚数是35×2=70(只),比题中所说的94只要少94-70=24(只)。
现在,我们松开一只兔子脚上的绳子,总的脚数就会增加2只,即70+2=72(只),再松开一只兔子脚上的绳子,总的脚数又增加2,2,2,2„„,一直继续下去,直至增加24,因此兔子数:24÷2=12(只),从而鸡有35-12=23(只)。
34、鸡、兔共笼,鸡比兔多26只,足数共274只,问鸡、兔各几只?
【答案】方法一:假设鸡有50只,那么兔就有24只,总脚数=50×2+24×4=196(只)
少的脚数=274-196=78(只)
因此还要增加鸡的只数,为了保持“差”是26,每增加一只鸡,同时要增加一只兔,所以增加的鸡数=78÷(4+2)=13(只),所以鸡数=50+13=63(只),兔数=24+13=37(只)
方法二:假设鸡和兔一样多,则先把少的兔脚加上少的兔脚=26×4=104(只)
鸡数=(104+274)÷(4+2)=63(只)
兔数=63-26=37(只)
35、已知一个等差数列第8项等于50,第15项等于71。请问:
(1)这个等差数列的第1项是多少?
(2)这个等差数列前10项的和是多少?
36、在一次数学竞赛中,获得一等奖的八名同学的分数恰好构成等差数列,总分为656,且第一名的分数超过了90分(满分100分)。已知同学们的分数都是整数,那么第三名的分数是多少?
37、计算 67×12+67×35+67×52+67 【答案】原式=67×(12+35+52+1)=67×100=6700
38、计算 85×85-84×86+83×87-82×88+81×89-80×90 【答案】原式=85×85-(85-1)(85+1)+(85-2)(85+2)-(85-3)(85+3)+(85-4)(85+4)-(85-5)(85+5)
=85×85-85×85+1+85×85-4-85×85+9+85×85-16-85×85+25=1-4+9-16+25=15
39、用杯子往一个空瓶里倒水,如果倒进6杯水,连瓶共重680克,如果倒进9杯水,连瓶共重920克。求空瓶的重量。40、小明、小红、小玲共有73块糖。如果小玲吃掉3块,那么小红与小玲的糖就一样多;如果小红给小明2块,那么小明的糖就是小红的糖的2倍。问:小红有多少块糖?
41、有一些三位数的各位数字都不是0,且各位数字之和为6,这样的三位数共有多少个? 【答案】对于不同情况进行枚举分析
(1)个位为1,那么十位+百位=5,所以有(1,4)、(2,3)、(3,2)、(4,1)四种情况;
(2)个位为2,那么十位+百位=4,所以有(1,3)、(2,2)、(3,1)三种情况;
(3)个位为3,那么十位+百位=3,所以有(1,2)、(2,1)二种情况;
(4)个位为4,那么十位+百位=2,所以有(1,1)一种情况;
(5)个位为5或6,那么十位+百位=1或0,不可能;
综上所述:这样的三位数共有1+2+3+4=10种情况
42、甲、乙、丙三个人传球,第一次传球是由甲开始,将球传给乙或丙„„经过4次传球后,球正好回到甲手中,那么一共有多少种不同的传球方式? 【答案】学会用树形图的方法
由图可知:一共有6种不同的传球方式
43、如图14-14,用四个完全相同的边长分别为5、12、13的直角三角形拼成了一个“风车”,求这个风车的周长。
44、如图14-22,一个正方体的8个顶点被截去后,得到一个新的几何体。这个新的几何体有几个面?几个顶点?几条棱?