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Problem of the Month Between the Lines © Noyce Foundation 2015. This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 Unported License (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.en_US). 1 Problem of the Month: Between the Lines The Problems of the Month (POM) are used in a variety of ways to promote problem solving and to foster the first standard of mathematical practice from the Common Core State Standards: “Make sense of problems and persevere in solving them.” The POM may be used by a teacher to promote problem solving and to address the differentiated needs of her students. A department or grade level may engage their students in a POM to showcase problem solving as a key aspect of doing mathematics. POMs can also be used school wide to promote a problem-solving theme at a school. The goal is for all students to have the experience of attacking and solving non-routine problems and developing their mathematical reasoning skills. Although obtaining and justifying solutions to the problems is the objective, the process of learning to problem-solve is even more important. The Problem of the Month is structured to provide reasonable tasks for all students in a school. The POM is designed with a shallow floor and a high ceiling, so that all students can productively engage, struggle, and persevere. The Primary Version is designed to be accessible to all students and especially as the key challenge for grades K – 1. Level A will be challenging for most second and third graders. Level B may be the limit of where fourth and fifth-grade students have success and understanding. Level C may stretch sixth and seventh-grade students. Level D may challenge most eighth and ninth-grade students, and Level E should be challenging for most high school students. These grade-level expectations are just estimates and should not be used as an absolute minimum expectation or maximum limitation for students. Problem solving is a learned skill, and students may need many experiences to develop their reasoning skills, approaches, strategies, and the perseverance to be successful. The Problem of the Month builds on sequential levels of understanding. All students should experience Level A and then move through the tasks in order to go as deeply as they can into the problem. There will be those students who will not have access into even Level A. Educators should feel free to modify the task to allow access at some level. Overview In the Problem of the Month Between the Lines, students use polygons to solve problems involving area. The mathematical topics that underlie this POM are the attributes of linear measurement, square measurement, two-dimensional geometry, area, the Pythagorean Theorem, and geometric justification. The problem asks students to explore polygons and the relationship of their areas in various problem situations. In the first level of the POM, students are presented with an outline of an irregularly-shaped animal and pattern blocks. The students are then asked to cover (tile) the interior regions with pattern blocks. The second part of the task involves the same figure, only flipped horizontally. They are asked to cover the

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Page 1: Problem of the Month: Between the Lines - Inside Mathematics

ProblemoftheMonth BetweentheLines©NoyceFoundation2015.ThisworkislicensedunderaCreativeCommonsAttribution-NonCommercial-NoDerivatives3.0UnportedLicense(http://creativecommons.org/licenses/by-nc-nd/3.0/deed.en_US).

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ProblemoftheMonth:BetweentheLines

TheProblemsoftheMonth(POM)areusedinavarietyofwaystopromoteproblemsolvingandtofosterthefirststandardofmathematicalpracticefromtheCommonCoreStateStandards:“Makesenseofproblemsandpersevereinsolvingthem.”ThePOMmaybeusedbyateachertopromoteproblemsolvingandtoaddressthedifferentiatedneedsofherstudents.AdepartmentorgradelevelmayengagetheirstudentsinaPOMtoshowcaseproblemsolvingasakeyaspectofdoingmathematics.POMscanalsobeusedschoolwidetopromoteaproblem-solvingthemeataschool.Thegoalisforallstudentstohavetheexperienceofattackingandsolvingnon-routineproblemsanddevelopingtheirmathematicalreasoningskills.Althoughobtainingandjustifyingsolutionstotheproblemsistheobjective,theprocessoflearningtoproblem-solveisevenmoreimportant.TheProblemoftheMonthisstructuredtoprovidereasonabletasksforallstudentsinaschool.ThePOMisdesignedwithashallowfloorandahighceiling,sothatallstudentscanproductivelyengage,struggle,andpersevere.ThePrimaryVersionisdesignedtobeaccessibletoallstudentsandespeciallyasthekeychallengeforgradesK–1.LevelAwillbechallengingformostsecondandthirdgraders.LevelBmaybethelimitofwherefourthandfifth-gradestudentshavesuccessandunderstanding.LevelCmaystretchsixthandseventh-gradestudents.LevelDmaychallengemosteighthandninth-gradestudents,andLevelEshouldbechallengingformosthighschoolstudents.Thesegrade-levelexpectationsarejustestimatesandshouldnotbeusedasanabsoluteminimumexpectationormaximumlimitationforstudents.Problemsolvingisalearnedskill,andstudentsmayneedmanyexperiencestodeveloptheirreasoningskills,approaches,strategies,andtheperseverancetobesuccessful.TheProblemoftheMonthbuildsonsequentiallevelsofunderstanding.AllstudentsshouldexperienceLevelAandthenmovethroughthetasksinordertogoasdeeplyastheycanintotheproblem.TherewillbethosestudentswhowillnothaveaccessintoevenLevelA.Educatorsshouldfeelfreetomodifythetasktoallowaccessatsomelevel.OverviewIntheProblemoftheMonthBetweentheLines,studentsusepolygonstosolveproblemsinvolvingarea.ThemathematicaltopicsthatunderliethisPOMaretheattributesoflinearmeasurement,squaremeasurement,two-dimensionalgeometry,area,thePythagoreanTheorem,andgeometricjustification.Theproblemasksstudentstoexplorepolygonsandtherelationshipoftheirareasinvariousproblemsituations.InthefirstlevelofthePOM,studentsarepresentedwithanoutlineofanirregularly-shapedanimalandpatternblocks.Thestudentsarethenaskedtocover(tile)theinteriorregionswithpatternblocks.Thesecondpartofthetaskinvolvesthesamefigure,onlyflippedhorizontally.Theyareaskedtocoverthe

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regionagainusingadifferentarrangement.InLevelB,studentsarepresentedwithasetofisoscelestrapezoidsthatarescaledlargerbyalinearfactor.Thestudentsareaskedtocovertheareaofeachtrapezoidwithunittrapezoids.Theyarealsoaskedtoexaminethegrowthinthesizeoftheareaandtofindapattern.InLevelC,studentsaregivenagroupoftrianglesdrawnondotpaper.Thestudentsareaskedtofindtheareaofeachofthetriangles.InLevelD,thestudentsexplorealogodesignthatinvolvesthreesquaresofdifferingsizespositionedonthepaper.Thestudentsgrapplewithfindingarelationshipamongthethreesquares.InLevelE,studentsareshownhowthreetrianglesareconstructedinastepwiseprocess.Theyareaskedtodeterminearelationshipbetweenthethreetriangles.Studentsareaskedtojustifytheirsolutions.MathematicalConceptsInthisPOM,studentsexploretherelationshipoftheareaofpolygons.Studentsusepolygonsinspatialvisualization,tessellationandareaproblems.LaterinthePOM,studentswilluseknowledgeofarea,geometricpropertiesandthePythagoreanTheorem,aswellasreasoningandjustification,todetermineandverifyproblemsinvolvinggeometryandmeasurement.

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ProblemoftheMonth

BetweentheLines LevelABrianhascreatedanewanimalusingpatternblocks.Hetracedtheoutsideofhisanimal.Below is the outline of his animal.Whichpatternblocksdidheuse tomakehis animal?Showhowhemadehisanimal.

Canyoumakethesameanimalagainusingsomedifferentpatternblocks?Nowitisfacingintheotherdirection,show a different way to make theanimalwithpatternblocks.

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LevelBStartwithanisoscelestrapezoid,thesamesizeasthepatternblock.1.Useonlythepatternblocktrapezoidstotileandcoverthetrapezoiddrawnbelow.Howmanypatternblocktrapezoidsdoesit taketotiletheabovetrapezoid?Howaretheblocksarranged?Istheremorethanonearrangementyoucanmake?2.Useonlythepatternblocktrapezoidstotileandcoverthetrapezoiddrawnbelow.Howmanypatternblocktrapezoidsdoesittaketotiletheabovetrapezoid?Howaretheblocksarranged?Istheremorethanonearrangementyoucanmake?

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3.Usethepatternblocktrapezoidstotileandcoverthetrapezoiddrawnbelow:Howmanypatternblocktrapezoidsdoesittaketotiletheabovetrapezoid?Howaretheblocksarranged?Istheremorethanonearrangementyoucanmake?4.Usethepatternblocktrapezoidstotileandcoverthetrapezoiddrawnbelow.Howmanypatternblocktrapezoidsdoesittaketotiletheabovetrapezoid?Howaretheblocksarranged?Istheremorethanonearrangementyoucanmake?Examine the tiling arrangements youmade in figures 1 – 4.What patterns can you see?Howistheareagrowing?Explainwhythepatternsmakesense.

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LevelCFindtheareaofthesetriangles.

Explainyourreasoning.

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LevelDAhightechcompanyhasdesignedanewcompanylogousingthreesquares.Whataretherelationshipsbetweenthesizesofthethreesquares?Explainyourfindings.

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LevelEGivenanytwosquaresAandB-theycanbearrangedtoshareonevertexthatformsananglebetween0ºand180º.A third square C can be foundwhich has a side length equal to the distance between adifferentvertexofsquareAandadifferentvertexofsquareB(shownbelow),thusformingatriangularregionbetweenthethreesquares(coloredblack).

A B

A

B

A

B

C

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A line segment can be drawn between the vertices of the squares, forming three moretriangles(eachshadedwhite).What are the relationships between the threewhite triangles? What is the relationshipbetween the black triangle and the threewhite triangles? Explain and justifywhat youknow.

A

B

C

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ProblemoftheMonth

BetweentheLines

PrimaryVersionLevelAMaterials:Asetofpatternblocksforeachpairorapageoftheprintedpatternblockscutout,acopyoftheoutlineoftheanimalfacingbothdirections,gluestick,pencilandpaper.Discussion on the rug: Teacher shows the pattern blocks. “Here are the pattern blocks. What do you notice about them?” Teachercontinuestoaskchildrentonoticethat theyaredifferentcolors, shapes, sizesanddifferent length. The teacherencouragesthestudentstoplaywiththemandmakedifferentthings. Insmallgroups: Eachgrouphasasetofpatternblocks/ 1. Which of these blocks do we know? What is its name? How many sides does it have? How many corners does it have? Introducethenameofblocksoncethestudentsdemonstrateknowledgeoftheirattributes. 2. A boy named Brian made a picture of a new animal using pattern blocks. Here is the outline of the animal. Can you make Brian’s animal using pattern blocks? Show me how you made it. 3. There is a second picture of the animal. It is looking in a different direction. Can you make Brian’s animal using pattern blocks? Show me how you made it. At the end of the investigation have students draw either a picture, paste a picture ordictatearesponsetorepresenttheirsolution.

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Level A (Actual Pattern Block Template)

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Level A , Part 2 (Actual Pattern Block Template)

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Level B (Actual Pattern Block Template) Part 1 Part 2

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Level B (Actual Pattern Block Template) Part 3

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Level B (Actual Pattern Block Template) Part 4

Page 18: Problem of the Month: Between the Lines - Inside Mathematics

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ProblemoftheMonthBetweentheLines

TaskDescription–LevelAThistaskchallengesstudentstovisualizeafigurewithdifferentconfigurationsfromasetofshapes(triangles,squares,rhombi,trapezoids,and/orhexagons).Thisdevelopmentofspatialsensewillsupportthedevelopingunderstandingsofattributesinplanegeometryandtheuseofbasictransformations.

CommonCoreStateStandardsMath-ContentStandardsGeometryIdentifyanddescribeshapes(squares,circles,triangles,rectangles,hexagons,cubes,cones,cylinders,andspheres).K.G.1Describeobjectsintheenvironmentusingnamesofshapes,anddescribetherelativepositionsoftheseobjectsusingtermssuchasabove,below,beside,infrontof,behind,andnextto.K.G.2Correctlynameshapesregardlessoftheirorientationsoroverallsize.Analyze,compare,create,andcomposeshapes.K.G.6Composesimpleshapestoformlargershapes.Reasonwithshapesandtheirattributes.1.G.1Distinguishbetweendefiningattributes(e.g.,trianglesareclosedandthreesided)versusnon-definingattributes(e.g.,color,orientation,overallsize);buildanddrawshapestopossessdefiningattributes.1.G.2Composetwo-dimensionalshapes(rectangles,squares,trapezoids,triangles,half-circles,andquarter-circles)orthree-dimensionalshapes(cubes,rightrectangularprisms,rightcircularcones,andrightcircularcylinders)tocreateacompositeshape,andcomposenewshapesfromthecompositeshape.*

*Studentsdonotneedtolearnformalnamessuchas“rightrectangularprism.”Reasonwithshapesandtheirattributes.2.G.1Recognizeanddrawshapeshavingspecifiedattributes,suchasagivennumberofanglesoragivennumberofequalfaces.**Identifytriangles,quadrilaterals,pentagons,hexagons,andcubes.

**Sizesarecompareddirectlyorvisually,notcomparedbymeasuring.CommonCoreStateStandardsMath–StandardsofMathematicalPractice

MP.6 Attendtoprecision.Mathematicallyproficientstudentstrytocommunicatepreciselytoothers.Theytrytousecleardefinitionsindiscussionwithothersandintheirownreasoning.Theystatethemeaningofthesymbolstheychoose,includingusingtheequalsignconsistentlyandappropriately.Theyarecarefulaboutspecifyingunitsofmeasure,andlabelingaxestoclarifythecorrespondencewithquantitiesinaproblem.Theycalculateaccuratelyandefficiently,expressnumericalanswerswithadegreeofprecisionappropriatefortheproblemcontext.Intheelementarygrades,studentsgivecarefullyformulatedexplanationstoeachother.Bythetimetheyreachhighschooltheyhavelearnedtoexamineclaimsandmakeexplicituseofdefinitions.MP.7Lookforandmakeuseofstructure.Mathematicallyproficientstudentslookcloselytodiscernapatternorstructure.Youngstudents,forexample,mightnoticethatthreeandsevenmoreisthesameamountassevenandthreemore,ortheymaysortacollectionofshapesaccordingtohowmanysidestheshapeshave.Later,studentswillsee7x8equalsthewell-remembered7x5+7x3,inpreparationforlearningaboutthedistributiveproperty.Intheexpressionx2+9x+14,olderstudentscanseethe14as2x7andthe9as2+7.Theyrecognizethesignificanceofanexistinglineinageometricfigureandcanusethestrategyofdrawinganauxiliarylineforsolvingproblems.Theyalsocanstepbackforanoverviewandshiftperspective.Theycanseecomplicatedthings,suchassomealgebraicexpressions,assingleobjectsorasbeingcomposedofseveralobjects.Forexample,theycansee5–3(x–y)2as5minusapositivenumbertimesasquareandusethattorealizethatitsvaluecannotbemorethan5foranyrealnumbersxandy.

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ProblemoftheMonthBetweentheLines

TaskDescription–LevelBThistaskchallengesstudentstovisualizedifferentwaystoconfigurefourdifferentsizedtrapezoids,usinganisoscelestrapezoidastheunitwhole.Thistaskthenchallengesstudentstonoticepatternsthatcanbeseenintheconstructionofthesefourfigures-suchastherelationshipbetweenlineardimensionsofthefourisoscelestrapezoidsandtheirareas.Thisdevelopmentofspatialsensewillsupportthedevelopingunderstandingsofattributesinplanegeometryandtheuseofbasictransformations,andthisexplorationofpatternswillsupportthedevelopingunderstandingoffunctionalrelationships.

CommonCoreStateStandardsMath-ContentStandardsGeometryReasonwithshapesandtheirattributes.1.G.1Distinguishbetweendefiningattributes(e.g.,trianglesareclosedandthreesided)versusnon-definingattributes(e.g.,color,orientation,overallsize);buildanddrawshapestopossessdefiningattributes.1.G.2Composetwo-dimensionalshapes(rectangles,squares,trapezoids,triangles,half-circles,andquarter-circles)orthree-dimensionalshapes(cubes,rightrectangularprisms,rightcircularcones,andrightcircularcylinders)tocreateacompositeshape,andcomposenewshapesfromthecompositeshape.*

*Studentsdonotneedtolearnformalnamessuchas“rightrectangularprism.”Reasonwithshapesandtheirattributes.2.G.1Recognizeanddrawshapeshavingspecifiedattributes,suchasagivennumberofanglesoragivennumberofequalfaces.**Identifytriangles,quadrilaterals,pentagons,hexagons,andcubes.

**Sizesarecompareddirectlyorvisually,notcomparedbymeasuring.Reasonwithshapesandtheirattributes.3.G.2Partitionshapesintopartswithequalareas.Expresstheareaofeachpartasaunitfractionofthewhole.Forexample,partitionashapeinto4partswithequalarea,anddescribetheareaofeachpartas¼oftheareaoftheshape.OperationsandAlgebraicThinkingGenerateandanalyzepatterns.4.OA.5Generateanumberorshapepatternthatfollowsagivenrule.Identifyapparentfeaturesofthepatternthatwerenotexplicitintheruleitself.FunctionsDefine,evaluate,andcomparefunctions.8.F.1Understandthatafunctionisarulethatassignstoeachinputexactlyoneoutput.Thegraphofafunctionisthesetoforderedpairsconsistingofaninputandthecorrespondingoutput.HighSchool–Functions-BuildingFunctionsBuildafunctionthatmodelsarelationshipbetweentwoquantities.F-BF.1Writeafunctionthatdescribesarelationshipbetweentwoquantities.F-BF.1a.Determineanexplicitexpression,arecursiveprocess,orstepsforcalculationfromacontext.

CommonCoreStateStandardsMath–StandardsofMathematicalPracticeMP.6 Attendtoprecision.Mathematicallyproficientstudentstrytocommunicatepreciselytoothers.Theytrytousecleardefinitionsindiscussionwithothersandintheirownreasoning.Theystatethemeaningofthesymbolstheychoose,includingusingtheequalsignconsistentlyandappropriately.Theyarecarefulaboutspecifyingunitsofmeasure,andlabelingaxestoclarifythecorrespondencewithquantitiesinaproblem.Theycalculateaccuratelyandefficiently,expressnumericalanswerswithadegreeofprecisionappropriatefortheproblemcontext.Intheelementarygrades,studentsgivecarefullyformulatedexplanationstoeachother.Bythetimetheyreachhighschooltheyhavelearnedtoexamineclaimsandmakeexplicituseofdefinitions.MP.7Lookforandmakeuseofstructure.Mathematicallyproficientstudentslookcloselytodiscernapatternorstructure.Youngstudents,forexample,mightnoticethatthreeandsevenmoreisthesameamountassevenandthreemore,ortheymaysortacollectionofshapesaccordingtohowmanysidestheshapeshave.Later,studentswillsee7x8equalsthewell-remembered7x5+7x3,inpreparationforlearningaboutthedistributiveproperty.Intheexpressionx2+9x+14,olderstudentscanseethe14as2x7andthe9as2+7.Theyrecognizethesignificanceofanexistinglineinageometricfigureandcanusethestrategyofdrawinganauxiliarylineforsolvingproblems.Theyalsocanstepbackforanoverviewandshiftperspective.Theycanseecomplicatedthings,suchassomealgebraicexpressions,assingleobjectsorasbeingcomposedofseveralobjects.Forexample,theycansee5–3(x–y)2as5minusapositivenumbertimesasquareandusethattorealizethatitsvaluecannotbemorethan5foranyrealnumbersxandy.

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ProblemoftheMonthBetweentheLines

TaskDescription–LevelCThistaskchallengesstudentstofindtheareasofdifferenttypesoftrianglesongeoboardgridpaper.Anunderstandingoftherelationshipsbetweenrectanglesandtrianglesisoneavenuefordeterminingtheseareas.

CommonCoreStateStandardsMath-ContentStandardsMeasurementandDataGeometricmeasurement:understandconceptsofareaandrelateareatomultiplicationandtoaddition.3.MD.5Recognizeareaasanattributeofplanefiguresandunderstandconceptsofareameasurement.3.MD.5a.Asquarewithsidelength1unit,called“aunitsquare,”issaidtohave“onesquareunit”ofarea,andcanbeusedtomeasurearea.3.MD.5b.Aplanefigurewhichcanbecoveredwithoutgapsoroverlapsbynunitsquaresissaidtohaveanareaofnsquareunits.3.MD.6Measureareasbycountingunitsquares(squarecm,squarem,squarein,squareft,andimprovisedunits).Drawandidentifylinesandangles,andclassifyshapesbypropertiesoftheirlinesandangles.4.G.1Classifytwo-dimensionalfiguresbasedonthepresenceorabsenceofparallelorperpendicularlines,orthepresenceorabsenceofanglesofaspecifiedsize.Recognizerighttrianglesasacategory,andidentifyrighttriangles.Solvereal-worldandmathematicalproblemsinvolvingarea,surfacearea,andvolume.6.G.1Findtheareaofrighttriangles,othertriangles,specialquadrilaterals,andpolygonsbycomposingintorectanglesordecomposingintotrianglesandothershapes;applythesetechniquesinthecontextofreal-worldandmathematicalproblems.

CommonCoreStateStandardsMath–StandardsofMathematicalPracticeMP.6Attendtoprecision.Mathematicallyproficientstudentstrytocommunicatepreciselytoothers.Theytrytousecleardefinitionsindiscussionwithothersandintheirownreasoning.Theystatethemeaningofthesymbolstheychoose,includingusingtheequalsignconsistentlyandappropriately.Theyarecarefulaboutspecifyingunitsofmeasure,andlabelingaxestoclarifythecorrespondencewithquantitiesinaproblem.Theycalculateaccuratelyandefficiently,expressnumericalanswerswithadegreeofprecisionappropriatefortheproblemcontext.Intheelementarygrades,studentsgivecarefullyformulatedexplanationstoeachother.Bythetimetheyreachhighschooltheyhavelearnedtoexamineclaimsandmakeexplicituseofdefinitions.MP.7Lookforandmakeuseofstructure.Mathematicallyproficientstudentslookcloselytodiscernapatternorstructure.Youngstudents,forexample,mightnoticethatthreeandsevenmoreisthesameamountassevenandthreemore,ortheymaysortacollectionofshapesaccordingtohowmanysidestheshapeshave.Later,studentswillsee7x8equalsthewell-remembered7x5+7x3,inpreparationforlearningaboutthedistributiveproperty.Intheexpressionx2+9x+14,olderstudentscanseethe14as2x7andthe9as2+7.Theyrecognizethesignificanceofanexistinglineinageometricfigureandcanusethestrategyofdrawinganauxiliarylineforsolvingproblems.Theyalsocanstepbackforanoverviewandshiftperspective.Theycanseecomplicatedthings,suchassomealgebraicexpressions,assingleobjectsorasbeingcomposedofseveralobjects.Forexample,theycansee5–3(x–y)2as5minusapositivenumbertimesasquareandusethattorealizethatitsvaluecannotbemorethan5foranyrealnumbersxandy.

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ProblemoftheMonth:BetweentheLines

TaskDescription–LevelDThistaskchallengesstudentstofindtherelationshipbetweenthesizesofthreegivenoverlappingsquares.Anunderstandingofanglerelationshipsanddefinitions,congruency,andthePythagoreanTheoremdeepenstudents’understandingandaccesstothemathematicsinthislevel.

CommonCoreStateStandardsMath-ContentStandardsGeometryUnderstandcongruenceandsimilarityusingphysicalmodels,transparencies,orgeometrysoftware.8.G.2Understandthatatwo-dimensionalfigureiscongruenttoanotherifthesecondcanbeobtainedfromthefirstbyasequenceofrotations,reflections,andtranslations;giventwocongruentfigures,describeasequencethatexhibitsthecongruencebetweenthem.UnderstandandapplythePythagoreanTheorem.8.G.7ApplythePythagoreanTheoremtodetermineunknownsidelengthsinrighttrianglesinreal-worldandmathematicalproblemsintwoandthreedimensions.HighSchool–Geometry-CongruenceUnderstandcongruenceintermsofrigidmotionsG-CO.7Usethedefinitionofcongruenceintermsofrigidmotionstoshowthattwotrianglesarecongruentifandonlyifcorrespondingpairsofsidesandcorrespondingpairsofanglesarecongruent.ProvegeometrictheoremsG-CO.9Provetheoremsaboutlinesandangles.Theoremsinclude:verticalanglesarecongruent;whenatransversalcrossesparallellines,alternateinterioranglesarecongruentandcorrespondinganglesarecongruent;pointsonaperpendicularbisectorofalinesegmentareexactlythoseequidistantfromthesegment’sendpoints.G-CO.10Provetheoremsabouttriangles.Theoremsinclude:measuresofinterioranglesofatrianglesumto180!;baseanglesofisoscelestrianglesarecongruent;thesegmentjoiningmidpointsoftwosidesofatriangleisparalleltothethirdsideandhalfthelength;themediansofatrianglemeetatapoint.

CommonCoreStateStandardsMath–StandardsofMathematicalPracticeMP.6Attendtoprecision.Mathematicallyproficientstudentstrytocommunicatepreciselytoothers.Theytrytousecleardefinitionsindiscussionwithothersandintheirownreasoning.Theystatethemeaningofthesymbolstheychoose,includingusingtheequalsignconsistentlyandappropriately.Theyarecarefulaboutspecifyingunitsofmeasure,andlabelingaxestoclarifythecorrespondencewithquantitiesinaproblem.Theycalculateaccuratelyandefficiently,expressnumericalanswerswithadegreeofprecisionappropriatefortheproblemcontext.Intheelementarygrades,studentsgivecarefullyformulatedexplanationstoeachother.Bythetimetheyreachhighschooltheyhavelearnedtoexamineclaimsandmakeexplicituseofdefinitions.MP.7Lookforandmakeuseofstructure.Mathematicallyproficientstudentslookcloselytodiscernapatternorstructure.Youngstudents,forexample,mightnoticethatthreeandsevenmoreisthesameamountassevenandthreemore,ortheymaysortacollectionofshapesaccordingtohowmanysidestheshapeshave.Later,studentswillsee7x8equalsthewell-remembered7x5+7x3,inpreparationforlearningaboutthedistributiveproperty.Intheexpressionx2+9x+14,olderstudentscanseethe14as2x7andthe9as2+7.Theyrecognizethesignificanceofanexistinglineinageometricfigureandcanusethestrategyofdrawinganauxiliarylineforsolvingproblems.Theyalsocanstepbackforanoverviewandshiftperspective.Theycanseecomplicatedthings,suchassomealgebraicexpressions,assingleobjectsorasbeingcomposedofseveralobjects.Forexample,theycansee5–3(x–y)2as5minusapositivenumbertimesasquareandusethattorealizethatitsvaluecannotbemorethan5foranyrealnumbersxandy.

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CCSSMAlignment:ProblemoftheMonth BetweentheLines©NoyceFoundation2015.ThisworkislicensedunderaCreativeCommonsAttribution-NonCommercial-NoDerivatives3.0UnportedLicense(http://creativecommons.org/licenses/by-nc-nd/3.0/deed.en_US).

ProblemoftheMonthBetweentheLines

TaskDescription–LevelEThistaskchallengesstudentstohaveastrongunderstandingoftransformationalgeometryandpropertiesoftriangles.

CommonCoreStateStandardsMath-ContentStandardsHighSchool–Geometry–CongruenceExperimentwithtransformationsintheplaneG-CO.2Representtransformationsintheplaneusing,e.g.,transparenciesandgeometrysoftware;describetransformationsasfunctionsthattakepointsintheplaneasinputsandgiveotherpointsasoutputs.Comparetransformationsthatpreservedistanceandangletothosethatdonot(e.g.,translationversushorizontalstretch).G-CO.3Givenarectangle,parallelogram,trapezoidorregularpolygon,describetherotationsandreflectionsthatcarryitontoitself.G-CO.4Developdefinitionsofrotations,reflections,andtranslationsintermsofangles,circles,perpendicularlines,parallellines,andlinesegments.UnderstandcongruenceintermsofrigidmotionsG-CO.7Usethedefinitionofcongruenceintermsofrigidmotionstoshowthattwotrianglesarecongruentifandonlyifcorrespondingpairsofsidesandcorrespondingpairsofanglesarecongruent.

CommonCoreStateStandardsMath–StandardsofMathematicalPracticeMP.6Attendtoprecision.Mathematicallyproficientstudentstrytocommunicatepreciselytoothers.Theytrytousecleardefinitionsindiscussionwithothersandintheirownreasoning.Theystatethemeaningofthesymbolstheychoose,includingusingtheequalsignconsistentlyandappropriately.Theyarecarefulaboutspecifyingunitsofmeasure,andlabelingaxestoclarifythecorrespondencewithquantitiesinaproblem.Theycalculateaccuratelyandefficiently,expressnumericalanswerswithadegreeofprecisionappropriatefortheproblemcontext.Intheelementarygrades,studentsgivecarefullyformulatedexplanationstoeachother.Bythetimetheyreachhighschooltheyhavelearnedtoexamineclaimsandmakeexplicituseofdefinitions.MP.7Lookforandmakeuseofstructure.Mathematicallyproficientstudentslookcloselytodiscernapatternorstructure.Youngstudents,forexample,mightnoticethatthreeandsevenmoreisthesameamountassevenandthreemore,ortheymaysortacollectionofshapesaccordingtohowmanysidestheshapeshave.Later,studentswillsee7x8equalsthewell-remembered7x5+7x3,inpreparationforlearningaboutthedistributiveproperty.Intheexpressionx2+9x+14,olderstudentscanseethe14as2x7andthe9as2+7.Theyrecognizethesignificanceofanexistinglineinageometricfigureandcanusethestrategyofdrawinganauxiliarylineforsolvingproblems.Theyalsocanstepbackforanoverviewandshiftperspective.Theycanseecomplicatedthings,suchassomealgebraicexpressions,assingleobjectsorasbeingcomposedofseveralobjects.Forexample,theycansee5–3(x–y)2as5minusapositivenumbertimesasquareandusethattorealizethatitsvaluecannotbemorethan5foranyrealnumbersxandy.

Page 23: Problem of the Month: Between the Lines - Inside Mathematics

CCSSMAlignment:ProblemoftheMonth BetweentheLines©NoyceFoundation2015.ThisworkislicensedunderaCreativeCommonsAttribution-NonCommercial-NoDerivatives3.0UnportedLicense(http://creativecommons.org/licenses/by-nc-nd/3.0/deed.en_US).

ProblemoftheMonthBetweentheLines

TaskDescription–PrimaryLevelThistaskchallengesstudentstonameanddefineattributesoftwo-dimensionalshapes(triangles,squares,rhombi,trapezoids,and/orhexagons).Thistaskalsochallengesstudentstorecognizeafigurewithtwodifferentorientationsfromasetofshapes(triangles,squares,rhombi,trapezoids,and/orhexagons).Thisdevelopmentofspatialsensewillsupportthedevelopingunderstandingofattributesinplanegeometryandtheuseofbasictransformations.

CommonCoreStateStandardsMath-ContentStandardsGeometryIdentifyanddescribeshapes(squares,circles,triangles,rectangles,hexagons,cubes,cones,cylinders,andspheres.)K.G.1Describeobjectsintheenvironmentusingnamesofshapes,anddescribetherelativepositionsoftheseobjectsusingtermssuchasabove,below,beside,infrontof,behind,andnextto.K.G.2Correctlynameshapesregardlessoftheirorientationsoroverallsize.Analyze,compare,create,andcomposeshapes.K.G.6Composesimpleshapestoformlargershapes.

CommonCoreStateStandardsMath–StandardsofMathematicalPracticeMP.6Attendtoprecision.Mathematicallyproficientstudentstrytocommunicatepreciselytoothers.Theytrytousecleardefinitionsindiscussionwithothersandintheirownreasoning.Theystatethemeaningofthesymbolstheychoose,includingusingtheequalsignconsistentlyandappropriately.Theyarecarefulaboutspecifyingunitsofmeasure,andlabelingaxestoclarifythecorrespondencewithquantitiesinaproblem.Theycalculateaccuratelyandefficiently,expressnumericalanswerswithadegreeofprecisionappropriatefortheproblemcontext.Intheelementarygrades,studentsgivecarefullyformulatedexplanationstoeachother.Bythetimetheyreachhighschooltheyhavelearnedtoexamineclaimsandmakeexplicituseofdefinitions.MP.7Lookforandmakeuseofstructure.Mathematicallyproficientstudentslookcloselytodiscernapatternorstructure.Youngstudents,forexample,mightnoticethatthreeandsevenmoreisthesameamountassevenandthreemore,ortheymaysortacollectionofshapesaccordingtohowmanysidestheshapeshave.Later,studentswillsee7x8equalsthewell-remembered7x5+7x3,inpreparationforlearningaboutthedistributiveproperty.Intheexpressionx2+9x+14,olderstudentscanseethe14as2x7andthe9as2+7.Theyrecognizethesignificanceofanexistinglineinageometricfigureandcanusethestrategyofdrawinganauxiliarylineforsolvingproblems.Theyalsocanstepbackforanoverviewandshiftperspective.Theycanseecomplicatedthings,suchassomealgebraicexpressions,assingleobjectsorasbeingcomposedofseveralobjects.Forexample,theycansee5–3(x–y)2as5minusapositivenumbertimesasquareandusethattorealizethatitsvaluecannotbemorethan5foranyrealnumbersxandy.