完整版四年級奧數(shù)第五講 等差數(shù)列二 學生版

1、唯思達教育小學四年級奧數(shù)一對一講義學生版第五講等差數(shù)列（二）解題方法某些問題以轉(zhuǎn)化為求若干個數(shù)的和解決這些問題時先要判斷這些數(shù)是否成為等差數(shù) 列，如果是等差數(shù)列才可以運用它的一些公式。在解決自然數(shù)的數(shù)字問題時，應根據(jù)題目的具體特點，有時可考慮將題中的數(shù)適當分 組，并將每組中的數(shù)合理配對，使問題得以順利解決。例題1小王看一本書第一天看了 20頁，以后每天都比前一天多看 2頁，第30天看了 78頁正好看完。這本書共有多少頁？引申1、文麗學英語單詞，第一天學會了 3個，以后每天都比前一天多學會 1個，最后一天學會了 21 個。文麗在這些天中共學會了多少個英語單詞？2、李師傅做一批零件，第一天做了25

2、個，以后每天都比前一天多做2個，第20天做了 63個正好做完。這批零件共有多少個？3、小李讀一本短篇小說，她第一天讀了20頁這個等差數(shù)列共有多少項 ？例題2建筑工地上堆著一些鋼管（如圖所示）,求這堆鋼管一共有多少根。小學四年級奧數(shù)第14頁共10頁oooocboooo引申,已知1、一些同樣粗細的圓木，像如圖所示一樣均勻地堆放在一起 最下面一層有70根。一共有多少根圓木？2、用3根等長的火柴棍擺成一個等邊三角形 ，用這樣的等邊三角形，按下圖所示鋪滿一個大 的等邊三角形，如果這個大的等邊三角形的底邊能放 10根火柴棒，那么這個大的等邊三角形 中一共要放多少根火柴棒 ？3、用相同的小立方體擺成如圖所示

3、的形狀，如果共擺成10層,那么最下面有多少個小立方體例題3有50把鎖的鑰匙搞亂了 ，為了使每把鎖都配上自己的鑰匙，至多要試多少次？引申1、有60把鎖的鑰匙搞亂了 ，為了使每把鎖都配上自己的鑰匙，至多試多少次？2、有一些鎖的鑰匙搞亂了，已知至多要試28次,就能使每把鎖都配上自己的鑰匙。一共有幾把鎖的鑰匙搞亂了 ？3、一輛公共汽車有66個座位,空車出發(fā)后,第一站上一位乘客,第二站上兩位乘客,第三站上 三位乘客,依次類推,第幾站后,車上坐滿乘客?例題4四（1）班45位同學舉行一次同學聯(lián)歡會，同學們在一起一一握手，且每兩個人只引申16人參加比賽,1、學校進行書法大賽，每個選手都要和其他所有選手各賽一場

4、。如果有 共要進行多少場比賽？2、在一次元旦晚會上，一共有48位同學和5位老師，每一位同學或老師都要和其他同學握次手。那么一共握了多少次手?28次。如果參加聚會的人和其余的每個人只握手3、一次朋友聚會，大家見面時總共握手 次，問參加聚會的共有多少人？Class:Name:()1. Good morning!A.Morni ng !B.Hello !C.Hi !()2. Nice to see you again !A.How are you ?B.Nice to see you , too .C.How do you do()3.Good ni ght,mom !A.Night !B.Good

5、 night !()4.How do you do ?A.How are you ?B.Fin e,tha nks .C.Good evening .C.How do you do)5.HowmanystorybooksdoyouhaveA.I have 10.B.l can see 10.()6.Do you have new teachers?B.Yes,we don t.)7.WhoB.Miss Zhu.A.Yes,we do .(teacher ?A.Mr Zhu.C.Thirty yua n.C.Yes,we have .syourC.He s tall.art()8.What s

6、he like?C.Mr Zhu.A. He s tall and strong .B.Yes,he is.()9.ls your En glish teacher young?C.No,she is.A. No,she isn t.B.Yes,she is .( )10.Her n ame is Che n Jie.A.What s your nameB. What s she nameC. What s her name( )11.I like Chin ese,math and En glish.A.What classes do you like?B.What do you like?

7、C.What are you like( )12.A.What do you have on Mo ndays ?C.What do you have on Mon day?()13.A.What is it today ? B.What day is it todayWe have En glish and P.E.B.What do you have ?It s Monday.C.What day is today()14.I watch TV and do my homework.A.What do you doB.What do you do in Mo ndays?C.What do

8、 you do on Sun days()15.May I have a look ?A.Sure.Here you are .B.Look !C.Here you are .()16.Our math teacher isCan ada.A.fromB.inC.at()17A.hasB.am C.have()18.What sthree new teachers.Chin ese teacher likeA.youB.yourC.you re()19.My P.E.teacher isthin.A.tooB.soC.very()20.There areA.sixB.seve ndays in

9、 a week.C.eightC.twelve()21.There areA.te nB.eleve n month(月)in a year( 年).Saturday .()22.I ofte n watch TVA.o nB.inC.at)23.1 like P.E.I don t lime music.A.butB.a ndC.so)24.Thisisapple.Itisred apple.A.a , aB.a n,an)25.WhatA.classesB.classC.a n, ado you likeC.class s六年級英語測試題Class:Name:()1. How are yo

10、u ?A.Fi ne,tha nks.B.Yes,it is.()2. Nice to meet you !A.Fi ne,tha nk you.B.OK.()3. How do you go to school ?C.How are youC.Nice to meet you ,too !A.I go to Can ada by pla ne. B.I go to school by bike.C.What about you)4.HowdoyougototheUSAC.I go by pla ne.My home is near theA.I usually go to school by

11、 bus. B.I go to En gla nd by ship.()5.post office.A. Where is your home ? B.OK.C.See you the n!()6. See you at 2 o clock.A.See you the n !B.The fifth floor.C.Its easy.()7.?You can go by the No.15bus.A.Its not far.B. How can 1 get to Zhon gsha n Park ?C.Sure.()8. Where is the hospital?C.YouA.Next to

12、the cin ema.B.Tha nk you .re welcome.)9.Excuseme ,istherecin eman earhere ?A.Yes,there is .B.No,itnot far.C.Its n ear the post office.office.)10.?It s near the postA.Yes,there is .B.No,itnot far.C. Where is the library?)11.It s next to the hospital.A. Where is the cin ema ,please ?B.Is it far ?C.Go

13、straight.()12. How can I get to the hospitalA.It s next to the hospital.B. You can go by the No.201 bus. C.Tha nk you.)13.Tha nk you .A.Tha nk you .B.OK.C.Youre welcome.)14. How can I get to the museum?A.Go straight.Then turn left.B.Tha nk you .C. It s east of the cinema .)15. Where is the post offi

14、ceA.Go straight.Then turn left.B.Tha nk you .C.It s east of the cinema .)16.Whatareyougoi ngtodothisevening ?A.I m going to the cinema .B.I go to school on foot.C.Yes,it is.()17. Is it farA.No,it is .B.Yes , it is .C.Yes,it isnt()18.do you go to school ?A.WhatB.WhereC.How()19.I go to schoolbike.A.o

15、nB.byC.get()20. Can I gofoot ?A.byB.atC.o n()21.How can Ito the post office ?A.n earB. getC.for()22.me.A. ExcuseB.HowC. next()23.birthday to you !A. AfterB.HappyC.First()24. The hospital isthe left.A. atB.inC.o n()25.is the bookstore ?A.WhereB.HowC.When四年級英語測試題Class:Name:( )1.Good afternoon !A.Hello

16、!B.Hi ! C.Afternoo n !( )2.Nice to see you aga in !A.How are you ? B.Hello ! C.Nice to see you , too.()3.Good ni ght,moom !A.Good evening ! B.Good n ight ! C.Night !( )4.How are you ?A.Fi ne,tha nk you .B.I am 10.C.Ni ne .( )5.How do you do ?A.Fi ne ,Tha nk you . B.How are you ? C.How do you do ? (

17、)6.How old are you ?A.How are you ? B.l am 11.()7.? I have 23.A.How many books do you have ? C.How many book do you have ?()8.? I can see 6.A.How many lights do you have ? C.How many light can you see ?( )9.May I have a look ?A.Sure.Here you are . B.Look!()10.? 50 yuan.A.How much is this schoolbag ?

18、 B.How many is this schoolbag ?C.l have 11.B.How many books can you see?B.How many lights can you see ?C.Sure.Here are you .C.How much are this schoolbag ?( )11.Where s my seat ?A.lt s near the door. B.lt s on the door. C.lt s under the door.()12.Let s clean the desks and chairs.A.All right !B.Hello

19、 !C.lt s nice .()13.What s this ?A.There is a board . B.lt s a bee. C.lt s bee.()14.? My n ame is Mike.A.Here are you ? B.What s your name ? C.How do you do ()15.Who s the inventor of paper ?A.Ch in ese people.B.Oh! Great ! C.Hello!()16 .la stude nt. Youa teacher.A.am ,amB.are, areC.am, areZhang Pen

20、g.( )17.Thisa boy.His n ameA.is, isB.am , is C.is , are()18 丄 etclean the fish bowl.A.lB. me C.my( )19.This is apple.lt isred apple .A.a n ,an B.a, aC.a n, a()20.Wea new classroom.A.are B.haveC.has()21.Therea bee in our classroom.A. is B.are C.am()22. have a new schoolbag. schoolbag is heavy.A.l , myB.l ,MyC.My , l()23.Put your En glish bookyour head.A.at B.in C.o n( )24.Theremany books in the desk.A.am B.isC.are