《Unit　4　Numbers课件》初中英语牛津上海版八年级上册课件53763PPT文档格式.pptx

《Unit　4　Numbers课件》初中英语牛津上海版八年级上册课件53763PPT文档格式.pptx

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Howmuchdoesapenusuallycost?

WhatisthepostcodeofGanxiang?

Reading（II）,Numbers:

Everyoneslanguage,OxfordEnglish8Apage57GanxiangSchoolZhangLili,Whatcanweusenumberstodo?

Weusethemtotellthetimeshowourage/countcalculate,Match,Zeroisanespeciallyimportantnumber.Inancienttimes,thereweredifferentwaysofwritingnumbers.YourbrainmaycalculatebetterthanacomputerMachinesmakeiteasierforustocalculate.,Egyptian埃及的,Chinese,Roman罗马的,Greek希腊的,6,However,theynearlyallcountedinthesameway-intens.,PartOneAncientnumbers,Inancienttimes，,Peoplewrotenumbersinmanydifferentways,Whatnumbersarethereinthesystemofnumbersthatmostofususe?

WhatdidtheIndiansinventfirst?

3.Whatdidtheyinventthen?

4.Whywasitaveryimportantinvention?

PartTwo,Zero,124589367,1.Whatnumbersarethereinthesystemofnumbersthatmostofususe?

PartTwo,Zero,124589367,WhatdidtheIndiansinventfirst?

The1to9systemofnumbers.Whatdidtheyinventthen?

Whywasitaveryimportantinvention?

Becauseitmadeiteasiertowritebignumbersandtocalculate.,36,7,124589,Ancientnumbers,Modernnumbers,WWhhiicchhnnuummbbeerrssaarreeeeaassiieerrtfoorwcpariletceou?

plaletein?

differentcountriestounderstandeachother?

anabacus,anelectroniccalculator,acomputer,PartThree,Calculatingmachines,Whydopeopleusethem?

calculatingmachines,features特点,ahumanbrain,15650=,Findthenumberthat,whenitismultiplied23timesbyitself,givesthisanswer:

916748676920039158098660927585380162483106680144308622407126516427934657040867096593279205767480806790022783016354924852380335745316935111903596577547340075681688305620821016129132845546805780158806771,a=,23,acomputer,Brainagainstcomputer,PartFour,aladyfromIndiawithanamazingbrain.,ShakuntalaDevi,Howlongdidittaketosolvethisproblem?

23,ShakuntalaDevi:

50secondsComputer:

60seconds,a=916748676920039158098660927585380162483106680144308622407126516427934657040867096593279205767480806790022783016354924852380335745316935111903596577547340075681688305620821016129132845546805780158806771a=?

546,372,891,Whichoneisamorepowerfulcalculator,ahumanbrainoracomputer?

Someonehadtofirstthe,computerwith,instructions,andthattook,hadtoprogram,manyhours.NooneShakuntala.,program,Agame:

1,2,3,4,5,6,7,8,Numbers,NumbersareWithnumbers,wecanWealsousethemtoTheymadeiteasiertoIftherearenonumbers,Sonumbersplayanimportantpartinourlife.,Listenandreadthetextonpage57threetimes.RecitenewwordsFindmoreinformationaboutnumbers.,Assignment,1.Anancientcalculatingmachinethatisstillusedtoday.Whatsit?

Anabacus.,2.ShakuntalaDeviisanIndianladywithanamazingbrain.,3.Whoinventedthe1to9systemofnumbers?

TheIndians.,4.Inancienttimes,peoplecountedintens.（oneword）,5.Averypowerfulmachinefordoingcalculations.Whatsit?

Acomputer.,6.Shakuntalasbrainworksveryfast.Itcandoacalculationlikelightning.,7.Whatcanamodernelectroniccalculatordo?

Itcanadd,subtract,multiply,anddivide.Itcanalsocalculatepercentagesandsquareroots.,8.Whydopeoplestilluseabacuses?

Theyaresofastandaccurate.,Completethesummary.,AncientnumbersInancienttimes,peoplewrotenumbers,buttheyarenearlycounted.ZeroEveryoneusesthe1to9and0（zero）.Theinventedthem.makesittowritebignumbersandtocalculate.CalculatingmachinesThethreecalculatingmachines:

the,theandthemakeourlifeeasier.BrainagainstcomputerTherewasonceacompetitionbetweenanIndianandainwhichthewon.Computerscannotdoanythingbythemselves.mustprogramthemfirst.,