《分数的意义》教学设计及反思.docx

《分数的意义》教学设计及反思.docx

《《分数的意义》教学设计及反思.docx》由会员分享，可在线阅读，更多相关《《分数的意义》教学设计及反思.docx（8页珍藏版）》请在冰豆网上搜索。

《分数的意义》教学设计及反思

《分数的意义》教学设计及反思（TeachingdesignandReflectiononthesignificanceoffraction）

TeachingdesignandReflectiononthesignificanceoffraction

YishuithirdexperimentalprimaryschoolQiuMeizhi

First,expandthemeaningof1/4

（a）apluralityofobjectsfromoneobjecttothe

1.doyouknowthescoreof1/4?

Canyougivemeanexample,whatisthe1/4?

1:

takeoneofthemooncakesweredividedinto4parts,oneofwhichisthatit's1/4

It'snicetothinkofmooncakes.What'stheaveragesizeofamooncake?

Can1ofthembeexpressedin1/4?

4Well,isthereanyexampleofthat?

Whocansayonemore1/4?

2:

acakeweredividedinto4parts,ofwhich1copiesofits1/4

Whoelsewouldliketotalkabout?

3:

putsomebooksweredividedinto4parts,eachofwhichis1/4.

Well,thestudentsaiddifferently.Hedividedsomebooksinto4parts,eachofwhichwas1/4ofthem.Agreed?

Isthereanythingelse?

Raw4:

?

......

Strange,allthingsareobviouslynotthesame,how1/4canbeusedtoexpress?

Student:

becauseallofthemweredividedinto4parts,oneofwhichis1/4.

Originally,canbeexpressedin1/4,andwhatisNevermind?

2.,thereseemstobealotof1/4inlife.Theteacheralsobringsonethingandwantstoknowwhatitis.Lookatthepicture.1apples

Thisapple,theaveragedistributiontofourpeople,eachperson'sshare,canbeusedtoexpress1/4?

Sheng:

energy

Agreewithhim?

Well,tosee,infigure（alotofApple）

Therearesomanyapples,whichareequallydistributedtofourpeople.Caneachpersonberepresentedby1/4?

Somestudentssaidyes,somestudentssaidno.

Let'sdotry.Theteacherpreparedsomewaferforeveryone,installedinyourgroupenvelope.Togetherwiththegroupoffourstudents,anduseittoreplacetheapple,theactualpoints.Nowthink,theseapplesequallyamongthefourofyou,eachshare,whatcannotbeused1/4toexpress.

Manualoperation.

Well,thestudentswereverycooperative.Allhavetheirownideas?

Who'sgoingtotalkaboutit?

Howmanyapplesarethereinyourgroup?

（Book:

8）doyouthinkthattheaveragedistributionof8applesto4people,eachperson'sshare,butalsocanbeusedtoexpress1/4?

Sheng:

energy

Well,Iputdownyourgroup.Conclusiontheothergroupiswhat?

Isit8apples?

Student:

weare12applescomponents.Eachofthe3,1/4canbeusedtoexpress

That'strue.Doyouhaveanyquestions?

Isthereanyotherdifference?

Writing:

12apples,16apples,20apples

Doyouhaveanyquestions?

Thereissomethingwrongwiththeteacher.Ourapplesareobviouslydifferent,8,12,16,andsoon.Whycananyoneuse1/4?

Student:

becauseallofthemdividedinto4.

That'sgreat!

So,canwith1/4points,andhowmuchthestuff?

Ifthereare200apples,averageto4people,eachpersoncan,canalsobeused?

（two）cognitionunit"1""

1.lookingback,whenwewerestudying1/4,weactuallylookedat1applesandmanyoftheseapplesasawhole.Aslongasthiswillbeawholehowyoucangetit,1/4?

Infact,whenwestudyotherfractions,weoftenneedtothinkofsuchanobject,ormanyobjects,asawhole.1applescanbeconsideredasawhole,8applescanberegardedasawhole,16apples?

Howabout21?

Inmathematics,peopleoftenusenaturalnumber1torepresentawhole,whichiscustomarilycalledunit1

2.think,besidesjusttheteacherfoundthat,lookaroundus,

Inourlife,whatelsedoyouthinkcanberegardedasawhole,thatis,unit1?

Sheng......

Isitpossible?

Thisexamplecanbefoundinlife?

（three）reunderstanding3/5.

Inadditiontothat,theteacheralsobroughtsomepictures,seeyouknow?

Figure:

around.Aroundcanberegardedas1units?

Look,ametercanberegardedas1units?

Whataboutthe5littlerabbits?

Thinkofthewholeofacircle,acupofteaandmanyflowersasunit1.What'sthenumberofparenthesesinthebracketsbelow?

3/5

Yousee?

Isee,butIhaveaproblemhere:

1unitsofthesame?

Whyareapartofthe3/5canbeusedtoexpress?

Student:

becausetheyaretheobjectofaveragedividedintothreeparts,thatis2ofthem.

Greatdiscovery.Althoughthe1arenotthesame,buttheyarewhat?

Soyoucanuseacommonfractionwhosaid?

Thatistosay,youcanuse3/5tosay,withtheunit1iswhatNevermind?

Two.Recognizeotherscores

1.throughlearning,wehaverecognizedtheunit1,themeaningof1/4and3/5alsohaveamoreprofoundunderstanding.Look,theteacheralsobringsscores.Whatdotheymean?

（pictures）doyouknow?

Whoknowsthescoreindicatesthemeaningofwhat?

Theteachergaveeachofthestudentstopreparesomematerials,therearemanyobjectsinacircle,thereisarectangularorsquare.Youcancombinethehandsofthematerial,chooseascorehere,todivide,fold,andslashafractionofwhatyoumostwanttosayit?

2.handsstartoperation.

3..Whatstudentshavecompletedtheirwork?

Pleaselookatyourworkonit,Itakewhatas1units,dividedintoseveralpieces,saidafewofthepainting?

Whichfractiondoyoumean?

Sheng:

......

OK？

Ihaveasuggestion,beforeandafterthegroupof4people,let'ssay:

Iputinthegroup......

Theteacheralsocollectedseveralstudents'works,canyouquicklyseewhatheisafewpoints?

Show.Theseworksarethesameasunit1?

Whycanbeusedtoexpressit?

Sheng:

......

Thisisthemeaningof2/3.Inthesamewaytoexchangetheothertwopoints.

Three,saidthescoresontheaxis

1.,themeaningofthesescores,wehaveadeeperunderstanding.Thinkaboutit,justnowwementionedsomanyunitsof1,canyoutakesuchalinesegmentisalsoconsideredasunit1?

Figure

From0to1asolongas1units,1/4saidwhat?

Sheng:

...

Teacher'sdiagram.1/4meansthatfrom0tothis,solong,andsometimeswejustusethispointtorepresent1/4.From0to1inthissection,wefindthe1/4position,the2/4?

Wehavealsofoundthe2.said2/3inthisline?

Tryityourself,drawapicture,find.

Rawoperation.Okay?

Say,howdoyoulookforit?

Theteacherreferstothescreen.Lookcloselyatthescreenandyourhomeworkpaper.Youthinkthepositionofthe2/5youfoundisveryaccurate.Raiseyourhand!

3.justnowwehavealotofmarksonthelinefrom0to1.Apartfromafewofthem,arethereanyotherscoresbetween0and1?

Then,thendownto,between1and2,thereisnoscore?

Between2and3?

You'reright。

Infact,inthemiddleoftheseintegers,lotsoffractionsaredotted,andfractions,likeintegers,areanewnumber.

Four,summarizethesignificanceoffractions

Wehavefurtherunderstandingofthescores,theteacheralsobroughtsomesmallexercises,youwanttotest,

Lookwho'sthequickest,okay?

Pleaselookatthepicturebelow,representsafractionofafew?

Sheng:

......

Theteacherasked:

thispicturesincetheysaidone-thirdofthenumber,whycolorstarisdifferent?

Student:

becausethetotalnumberisdifferent

Thatis,unit1isdifferent.Isthis?

Itiswhatitisreallyimportanttounit1.

Redrawing.

Isthisthesameasunit1?

Whyshowscoresbutnotthesame?

So,inordertoaccuratelyrepresentascore,wemustpayattentiontowhattheunit1is,andwhatshouldwepayattentionto?

Theaveragenumberofcopiesofthebook,saidthenumberofcopies.Themeaningofit,pointsout.

Five,expandtheapplication

1.throughthestudy,theunderstandingofthescoreastepfurther.Inourreallife,youhaveseenscores?

Theteachercollectedsucha:

Show:

accordingtostatistics,primaryschoolstudentsinourcountrymyopiaaccountedforabout1/5ofthetotalnumberofpeople.

Youmustknowthemeaningof1/5.Whosaid.

Whatdoyouthink?

Sheng:

......

Everyonefromthe1/5ofthefractionofonlyoccursthisfeeling.Itseemsasmallfractioncanofferusalotofinformation.Howmanymyopicstudentsarethereinourschool?

Handsup,please.Whatfractionofourstudentsmyopiaisappropriate?

Itlookslikethesituationisnotoptimistic.Whatdoyouthinkweshoulddo?

2..Seeadata（shown:

amapoftheworld）

Anestimateofthetotallandareaofabouttheareaoftheearth（）?

Theteacherprovidestwoscores,oneoftwo,whichisyourchoice?

Why?

Whatabouttheoceanarea?

3,theboysinourclassaccountedforthenumberofthewholeclass,whichmeans

（1）astheunit,theaverageisdividedinto（）,boysaccountedfor（）

Six,summary

Inthisclass,wewalkedbacktothescoreandunderstoodthesignificanceofthescore.Ihopeeveryoneoutoftheclassroomintolife,canfindmoremarks,tolearnmoreaboutthescoreknowledge!

Blackboardwritingdesign:

Significanceoffraction

1

8saidthenumberofcopies

12units,1

16oftheaveragenumberofcopies

Reflectionsonteaching:

InApril8thIparticipatedintheLinyiMunicipalOrganizationDepartmentoftheconstructionof"highclass"activities,injustonedaytimeislisteningtofourclass,ourschoolis"constructingefficientclassroom"activitiesaftertheendofthestudy,thefirststepistolistentotheclass,schoolleaderswanttoshowmeaclass.Listentothereviewofthefourclass,relativelydeepimpressionisLinshueducationschoolteacherLvJiantaughtthemeaningof"score",feelingteachingideasinthisclassteacherLudesignisrelativelyclear,teachingisrelativelycompact,thestudents'learningeffectisrelativelygood,socomebacktomeabouttrytoimitateit.Seeifyoucanmakethesameeffect.

ButnowIteachisthefourthgrade2,andthemeaningof"score"isthefifthgrade2contentXinlimeidi,firstfeelthestudentshavethebasicknowledgeisnotveryunderstanding,thenthefeelingofthisclassisaconceptofteaching,studentsneedtoexperience,maybeharderinsomewhenthelecture.ButlookingbacktoteacherLu'swonderfulclass,estimatedthatthed