tackling unstructured problems · 2017-10-29 · mason, j., burton, l. and stacey, k. (1982)...
TRANSCRIPT
(c)CentreforResearchinMathematicsEducation,UniversityofNottingham2010 1
TACKLINGUNSTRUCTUREDPROBLEMS
‘DoIstandbackandwatch,orinterveneandtellthemwhattodo?’
IntroductionInmostmathematicsandscienceclassrooms,studentsareprovidedwithstructuredtasksandaretoldpreciselywhichtechniquestodeploy.Studentslearnbyfollowinginstructions.Problemsandsituationsthatariseintheworldarenotusuallylikethis.Ratherthanbeingexercisesintheuseofaparticularskillorconcept,real-worldproblemsrequirestudentstomakesimplifications,modelsituations,chooseappropriateknowledgeandprocessesfromtheir'toolkit',andtestwhethertheirsolutionis"goodenough"forthepurposeinhand.Itseemslogicalthatifstudentsaretolearntousetheirskillsautonomouslyintheirfuturelives,theywillneedsomeopportunitiestoworkonlessstructuredproblemsintheirclassrooms.Thisunitcomparesstructuredandunstructuredversionsofproblemsandconsidersthedemandsandchallengesunstructuredproblemspresenttostudentsandteachers.
ActivitiesActivityA: Revisingstructuredproblems.......................................................................................2ActivityB: Comparestructuredandunstructuredproblems.........................................................4ActivityC: Considerstrategiesforofferinghelp.............................................................................6ActivityD: Observeandanalysealesson.......................................................................................8ActivityE: Planalesson,teachitandreflectontheoutcomes......................................................9Furtherreading................................................................................................................................10References.......................................................................................................................................10
Acknowledgement:ThismaterialisadaptedforPRIMASfrom:Swan,M;Pead,D(2008).Professionaldevelopmentresources.BowlandMathsKeyStage3,BowlandTrust/DepartmentforChildren,SchoolsandFamilies.AvailableonlineintheUKat:http://www.bowlandmaths.org.uk.ItisusedherebypermissionoftheBowlandTrust.
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ACTIVITYA:REVISINGSTRUCTUREDPROBLEMS
Timeneeded:20minutes.
Handout1presentsthreestructuredproblems:
• Organisingatabletennistournament• Designingaboxfor18sweets• CalculatingBodyMassIndex
TheseproblemsareofthesametypeasthosetypicallyfoundinmanyMathematicsandScienceClassrooms.Thefirsttwoarepracticalgrouptasksandthethirdisacomputer-basedtask.Theseare,however,structuredsothattheyleadstudentsthroughtheproblems,guidingandmakingdecisionsforthem.
• Workthroughoneofthestructuredproblemscarefully.• Listallthedecisionsthatarebeingmadeforthestudents.• Revisetheproblemssothatsomeofthesedecisionsarehandedbacktostudents.
Thiswillmakethemlessstructured.
Forexample,inOrganisingatabletennistournament,pupilsaretold:
• howtocodetheplayers(A,B,C..etc)• tolistallthematchesthatneedtobeplayed• howtosystematicallyorganisethesematches• howtotabulatetheorderofplay• torememberthatplayerscannotplayontwotablesatonce.
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Handout1:Structuredproblems
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ACTIVITYB:COMPARESTRUCTUREDANDUNSTRUCTUREDPROBLEMS
Timeneeded:10minutes
Handout2containsunstructuredversionsofthesametasksthatwereusedinactivityA.
• Comparethelessstructuredversionsoftheproblemswiththestructuredversions.• Whatdecisionshavebeenlefttothestudents?• Whatpedagogicalissueswillarisewhenyoustarttouseunstructuredproblemslikethis?
Someimmediateissuesthatteachersraiseare:
• Unstructuredproblemsaremoredifficult.• Itismoredifficulttoplanalessonwiththeseproblems.• Studentsmaynotevenknowhowtogetstartedonthem.Willwethereforeneedto
structurethemanyway?• Studentswillnotnecessarilyusewhatwehavetaughtthem.• Ifweofferhelptooquickly,studentswillsimplydowhatwesayandnotthinkfor
themselves.• Studentswillgenerateagreatervarietyofapproachesandsolutions.• StudentsmayneedreassurancethatitisOKtotryadifferentapproachorreachadifferent
conclusion.Handout3containssomenotesonthesolutionstothethreeproblems.
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Handout2:Unstructuredversionsoftheproblems
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ACTIVITYC:CONSIDERSTRATEGIESFOROFFERINGHELP
Timeneeded:30minutes.
Teachersoftenfinditdifficulttoknowwhentogivehelpandwhentoleavestudentsstruggling.Iftheyintervenetooquickly,thenthestudentshavenochancetoexperiencewhatitisliketopursueanunfruitfulidea,ortopuzzleoutasolutionforthemselves.Iftheyintervenetooslowly,thenstudentsbecomefrustrated,boredanddisengaged.Handout4containssomepracticaladvicewhenusingunstructuredproblems.Considerthisadvicecarefully:
• Whichideasdoyounormallyfindmostdifficulttoimplement?Whyisthis?• Isthereanyotheradviceyouwouldaddtothislist?Writeyourownideasatthebottom.
Brunerusesthemetaphorofscaffoldingtodescribethestructuringthatateacherprovides(D.Wood,Bruner,&Ross,1976).Theteacherencouragesstudentstoasmuchastheyarecapableofunaidedandonlyprovidestheminimumofsupporttohelpthemsucceed.Thissupportmayinvolvereducingtheirchoices,drawingattentiontoimportantfeaturesthroughquestioning,orevenattimesdemonstratingwhattodo.Inhisworkwithyoungchildren,Wood(1988)categoriseddifferentlevelsofscaffolding,fromlessdirectivetomoredirective:givinggeneralverbaladvice,givingspecificverbalinstructions,breakingtheproblemdown,demonstratingasolution.Woodalsointroducedtworulesofcontingency:
"Anyfailurebyachildtosucceedinanactionafteragivenlevelofhelpshouldbemetbyanimmediateincreaseinhelporcontrol.Successbyachildthenindicatesthatanysubsequentinstructionshouldofferlesshelpthanthatwhichprecededthesuccess,toallowthechildtodevelopindependence."Wood(1988)
Theimportantideahereisthatscaffoldingshouldberemovedasthestudentbeginstocope,otherwiseitreinforcesdependency.
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Handout4: Practicaladviceforteachingproblemsolving
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ACTIVITYD:OBSERVEANDANALYSEALESSON
Timeneeded:30minutes.
Thetwovideoclipsshowstudentsworkingwiththeunstructuredversionsofthesameproblemsyouhaveworkedon.WatchMichelleusingtheOrganisingatabletennistournamentproblem.Asyouwatchthevideo,consider:
• Howdidtheteacherorganisethelesson?Whatphasesdiditgothrough?• Whatresourcesdidtheteacherhaveavailable,andwhenweretheseused?• Whywerestudentsexpectedtoworkinpairs/smallgroups?• Howdidtheteacherintroducetheproblemtostudents?• Whatdifferentapproacheswerebeingusedbystudents?• Howdidtheteachersupportthestudentsthatwerestruggling?• Howdidtheteacherencouragethesharingofapproachesandstrategies?• Whatdoyouthinkthesestudentswerelearning?
AfterwardsyoumayenjoywatchingthesecondvideoclipofJudith'slessonwheresheaskstheclasstodesignaboxtohold18sweets.
Michellebeginsthelessonbyintroducingtheproblemandalsobyexplaininghowthestudentsshouldworktogether.Thestudentsarethengiven3-4minutestowritetheirindividual,initialideasofhowtheywilltackletheproblem.Thishelpsthemtoformulatetheirideasandhavesomeideastocontributetothegroupdiscussions.Studentswerethengivenafewminutestodiscusstheirideas.Thevideoshowsstudentsgettingtogripswiththeproblemandtheconstraintsinvolved.Someforexamplerealisethat4tableswillnotbeneeded.Atthispoint,Michelleintroducestheresourcesthatareavailableforthemtouse.Sheemphasisesthattheyshouldnotrushtheproblemsolvingandthatsomemaynotgetfinished.Shesaysthattheimportantthingistothinkabouttheapproaches.Whilegroupswork,Michellefirstlistens,thenintervenestopromotedeeperthinking:
"You'vefoundoneapproach.You'vefoundthatitisnotgoingtoquitework,isit?Sowhatdoweneedtodofromthere?"
"Re-readtheproblem.Lookatthelasttwosentences."
Studentsuseawiderangeofrepresentationsandresourcestosolvetheproblem.Someusedtables,whileothersusedcounters.Thesemethodsaresharedinthefinalwholediscussion.
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ACTIVITYE: PLANALESSON,TEACHITANDREFLECTONTHEOUTCOMES
Timeneeded:
• 15minutesdiscussionbeforethelesson• 1hourforthelesson• 15minutesafterthelesson
Chooseoneofthethreeproblemsthatyoufeelwouldbeappropriateforyourclass.Discusshowyouwill:
• Organisetheclassroomandtheresourcesneeded.• Introducetheproblemtopupils.• Explaintopupilshowyouwantthemtoworktogether.• Challenge/assistpupilsthatfindtheproblemstraightforward/difficult.• Helpthemshareandlearnfromalternativeproblem-solvingstrategies.• Concludethelesson.
Ifyouareworkingonthismodulewithagroup,itwillbehelpfulifeachparticipantchoosesthesameproblem,asthiswillfacilitatethefollow-updiscussion.Nowyouhavetaughtthelesson,itistimetoreflectonwhathappened.
• Whatrangeofresponsesdidpupilshavetothiswayofworking?Didsomeappearconfident?Didsomeneedhelp?Whatsortofhelp?Whydidtheyneedit?
• Whatsupportandguidancedidyoufeelobligedtogive?Whywasthis?Didyougivetoomuchortoolittlehelp?
• Whatdifferentstrategiesdidpupilsuse?Sharetwoorthreedifferentexamplesofpupils'work.
• Whatdoyouthinkpupilslearnedfromthislesson?
Ifthereistime,youmayalsoliketowatchthevideosoftheteachersastheyreflectontheirownlessonswiththeTabletennisandSweetboxproblems.
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FURTHERREADING
TheseminaltextforaskingpupilstothinkmathematicallyMason,J.,Burton,L.andStacey,K.(1982)ThinkingMathematically,London:Addison-WesleyThebookthatinspiredsomuchoftheresearchintoproblemsolvingheuristics(orwhattodowhenyouare'stuck')Polya,G.(1957)HowtoSolveIt:ANewAspectofMathematicalMethod,(2ndEd)PenguinScience.REFERENCES
Wood,D.(1988).HowChildrenThinkandLearn.OxfordandCambridge,MA:Blackwell.Wood,D.,Bruner,J.,&Ross,G.(1976).Theroleoftutoringinproblemsolving.Journalofchild
psychologyandpsychiatry,17,89-100.