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Glossary Additionandsubtractionwithin5,10,20,100,or1000.Additionorsubtractionoftwowhole numberswithwholenumberanswers,andwithsumorminuendintherange0Ͳ5,0Ͳ10,0Ͳ20,or0Ͳ 100,respectively.Example:8+2=10isanadditionwithin10,14–5=9isasubtractionwithin20, and55–18=37isasubtractionwithin100. Additiveinverses.Twonumberswhosesumis0areadditiveinversesofoneanother.Example:3/4 and–3/4areadditiveinversesofoneanotherbecause3/4+(–3/4)=(–3/4)+3/4=0. Associativepropertyofaddition.SeeTable3inthisGlossary. Associativepropertyofmultiplication.SeeTable3inthisGlossary. Bivariatedata.Pairsoflinkednumericalobservations.Example:alistofheightsandweightsforeach playeronafootballteam. Boxplot.Amethodofvisuallydisplayingadistributionofdatavaluesbyusingthemedian,quartiles, andextremesofthedataset.Aboxshowsthemiddle50%ofthedata.1 Commutativeproperty.SeeTable3inthisGlossary. Complexfraction.AfractionA/BwhereAand/orBarefractions(Bnonzero). Computationalgorithm.Asetofpredefinedstepsapplicabletoaclassofproblemsthatgivesthe correctresultineverycasewhenthestepsarecarriedoutcorrectly.Seealso:computationstrategy. Computationstrategy.Purposefulmanipulationsthatmaybechosenforspecificproblems,maynot haveafixedorder,andmaybeaimedatconvertingoneproblemintoanother.Seealso:computation algorithm. Congruent.Twoplaneorsolidfiguresarecongruentifonecanbeobtainedfromtheotherbyrigid motion(asequenceofrotations,reflections,andtranslations). Countingon.Astrategyforfindingthenumberofobjectsinagroupwithouthavingtocountevery memberofthegroup.Forexample,ifastackofbooksisknowntohave8booksand3morebooks areaddedtothetop,itisnotnecessarytocountthestackalloveragain.Onecanfindthetotalby 1 AdaptedfromWisconsinDepartmentofPublicInstruction,http://dpi.wi.gov/standards/mathglos.html,accessedMarch 2,2010. PrepublicationVersion,April2013 CaliforniaDepartmentofEducation 145| GLOSSARY countingon—pointingtothetopbookandsaying“eight,”followingthiswith“nine,ten,eleven. Thereareelevenbooksnow.” Dotplot.See:lineplot. Dilation.Atransformationthatmoveseachpointalongtheraythroughthepointemanatingfroma fixedcenter,andmultipliesdistancesfromthecenterbyacommonscalefactor. Expandedform.AmultiͲdigitnumberisexpressedinexpandedformwhenitiswrittenasasumof singleͲdigitmultiplesofpowersoften.Forexample,643=600+40+3. Expectedvalue.Forarandomvariable,theweightedaverageofitspossiblevalues,withweights givenbytheirrespectiveprobabilities. Firstquartile.ForadatasetwithmedianM,thefirstquartileisthemedianofthedatavaluesless thanM.Example:Forthedataset{1,3,6,7,10,12,14,15,22,120},thefirstquartileis6.2Seealso: median,thirdquartile,interquartilerange. Fraction.Anumberexpressibleintheforma/bwhereaisawholenumberandbisapositivewhole number.(ThewordfractioninthesestandardsalwaysreferstoanonͲnegativenumber.)Seealso: rationalnumber. Identitypropertyof0.SeeTable3inthisGlossary. Independentlycombinedprobabilitymodels.Twoprobabilitymodelsaresaidtobecombined independentlyiftheprobabilityofeachorderedpairinthecombinedmodelequalstheproductof theoriginalprobabilitiesofthetwoindividualoutcomesintheorderedpair. Integer.Anumberexpressibleintheformaor–aforsomewholenumbera. InterquartileRange.Ameasureofvariationinasetofnumericaldata,theinterquartilerangeisthe distancebetweenthefirstandthirdquartilesofthedataset.Example:Forthedataset{1,3,6,7,10, 12,14,15,22,120},theinterquartilerangeis15–6=9.Seealso:firstquartile,thirdquartile. Lineplot.Amethodofvisuallydisplayingadistributionofdatavalueswhereeachdatavalueisshown asadotormarkaboveanumberline.Alsoknownasadotplot.3 2 Manydifferentmethodsforcomputingquartilesareinuse.ThemethoddefinedhereissometimescalledtheMoore andMcCabemethod.SeeLangford,E.,“QuartilesinElementaryStatistics,”JournalofStatisticsEducationVolume14, Number3(2006). 3 AdaptedfromWisconsinDepartmentofPublicInstruction,op.cit. PrepublicationVersion,April2013 CaliforniaDepartmentofEducation 146| GLOSSARY Mean.Ameasureofcenterinasetofnumericaldata,computedbyaddingthevaluesinalistand thendividingbythenumberofvaluesinthelist.4Example:Forthedataset{1,3,6,7,10,12,14,15, 22,120},themeanis21. Meanabsolutedeviation.Ameasureofvariationinasetofnumericaldata,computedbyaddingthe distancesbetweeneachdatavalueandthemean,thendividingbythenumberofdatavalues. Example:Forthedataset{2,3,6,7,10,12,14,15,22,120},themeanabsolutedeviationis20. Median.Ameasureofcenterinasetofnumericaldata.Themedianofalistofvaluesisthevalue appearingatthecenterofasortedversionofthelist—orthemeanofthetwocentralvalues,ifthe listcontainsanevennumberofvalues.Example:Forthedataset{2,3,6,7,10,12,14,15,22,90}, themedianis11. Midline.Inthegraphofatrigonometricfunction,thehorizontallinehalfwaybetweenitsmaximum andminimumvalues. Multiplicationanddivisionwithin100.Multiplicationordivisionoftwowholenumberswithwhole numberanswers,andwithproductordividendintherange0Ͳ100.Example:72÷8=9. Multiplicativeinverses.Twonumberswhoseproductis1aremultiplicativeinversesofoneanother. Example:3/4and4/3aremultiplicativeinversesofoneanotherbecause3/4×4/3=4/3×3/4=1. Numberlinediagram.Adiagramofthenumberlineusedtorepresentnumbersandsupport reasoningaboutthem.Inanumberlinediagramformeasurementquantities,theintervalfrom0to1 onthediagramrepresentstheunitofmeasureforthequantity. Percentrateofchange.Arateofchangeexpressedasapercent.Example:ifapopulationgrowsfrom 50to55inayear,itgrowsby5/50=10%peryear. Probabilitydistribution.Thesetofpossiblevaluesofarandomvariablewithaprobabilityassignedto each. Propertiesofoperations.SeeTable3inthisGlossary. Propertiesofequality.SeeTable4inthisGlossary. Propertiesofinequality.SeeTable5inthisGlossary. Propertiesofoperations.SeeTable3inthisGlossary. 4 Tobemoreprecise,thisdefinesthearithmeticmean. PrepublicationVersion,April2013 CaliforniaDepartmentofEducation 147| GLOSSARY Probability.Anumberbetween0and1usedtoquantifylikelihoodforprocessesthathaveuncertain outcomes(suchastossingacoin,selectingapersonatrandomfromagroupofpeople,tossingaball atatarget,ortestingforamedicalcondition). Probabilitymodel.Aprobabilitymodelisusedtoassignprobabilitiestooutcomesofachance processbyexaminingthenatureoftheprocess.Thesetofalloutcomesiscalledthesamplespace, andtheirprobabilitiessumto1.Seealso:uniformprobabilitymodel. Randomvariable.Anassignmentofanumericalvaluetoeachoutcomeinasamplespace. Rationalexpression.AquotientoftwopolynomialswithanonͲzerodenominator. Rationalnumber.Anumberexpressibleintheforma/bor–a/bforsomefractiona/b.Therational numbersincludetheintegers. Rectilinearfigure.Apolygonallanglesofwhicharerightangles. Rigidmotion.Atransformationofpointsinspaceconsistingofasequenceofoneormore translations,reflections,and/orrotations.Rigidmotionsarehereassumedtopreservedistancesand anglemeasures. Repeatingdecimal.Thedecimalformofarationalnumber.Seealso:terminatingdecimal. Samplespace.Inaprobabilitymodelforarandomprocess,alistoftheindividualoutcomesthatare tobeconsidered. Scatterplot.Agraphinthecoordinateplanerepresentingasetofbivariatedata.Forexample,the heightsandweightsofagroupofpeoplecouldbedisplayedonascatterplot.5 Similaritytransformation.Arigidmotionfollowedbyadilation. Tapediagram.Adrawingthatlookslikeasegmentoftape,usedtoillustratenumberrelationships. Alsoknownasastripdiagram,barmodel,fractionstrip,orlengthmodel. Terminatingdecimal.Adecimaliscalledterminatingifitsrepeatingdigitis0. Thirdquartile.ForadatasetwithmedianM,thethirdquartileisthemedianofthedatavalues greaterthanM.Example:Forthedataset{2,3,6,7,10,12,14,15,22,120},thethirdquartileis15. Seealso:median,firstquartile,interquartilerange. 5 AdaptedfromWisconsinDepartmentofPublicInstruction,op.cit. PrepublicationVersion,April2013 CaliforniaDepartmentofEducation 148| GLOSSARY Transitivityprincipleforindirectmeasurement.IfthelengthofobjectAisgreaterthanthelengthof objectB,andthelengthofobjectBisgreaterthanthelengthofobjectC,thenthelengthofobjectA isgreaterthanthelengthofobjectC.Thisprincipleappliestomeasurementofotherquantitiesas well. Uniformprobabilitymodel.Aprobabilitymodelwhichassignsequalprobabilitytoalloutcomes.See also:probabilitymodel. Vector.Aquantitywithmagnitudeanddirectionintheplaneorinspace,definedbyanorderedpair ortripleofrealnumbers. Visualfractionmodel.Atapediagram,numberlinediagram,orareamodel. Wholenumbers.Thenumbers0,1,2,3,…. PrepublicationVersion,April2013 CaliforniaDepartmentofEducation 149| Table 1. Common addition and subtraction situations.6 GLOSSARY Result Unknown Add to Take from Twobunniesweresittingonthe Twobunniessatonthegrass. grass.Somemorebunnies Threemorebunnieshopped there.Howmanybunniesareon hoppedthere.Thentherewere fivebunnies.Howmanybunnies thegrassnow? hoppedovertothefirsttwo? 2+3=? 2+?=5 Compare9 Somebunniesweresittingon thegrass.Threemorebunnies hoppedthere.Thentherewere fivebunnies.Howmanybunnies wereonthegrassbefore? ?+3=5 Fiveappleswereonthetable.I atesomeapples.Thenthere werethreeapples.Howmany applesdidIeat? 5–?=3 Someappleswereonthetable.I atetwoapples.Thentherewere threeapples.Howmanyapples wereonthetablebefore? ?–2=3 Total Unknown Threeredapplesandtwogreen applesareonthetable.How Put Together/ manyapplesareonthetable? Take Apart8 3+2=? Start Unknown Fiveappleswereonthetable.I atetwoapples.Howmany applesareonthetablenow? 5–2=? Change Unknown Difference Unknown (“Howmanymore?”version): Lucyhastwoapples.Juliehas fiveapples.Howmanymore applesdoesJuliehavethan Lucy? (“Howmanyfewer?”version): Lucyhastwoapples.Juliehas fiveapples.Howmanyfewer applesdoesLucyhavethan Julie? 2+?=5,5–2=? Both Addends Unknown7 Addend Unknown Fiveapplesareonthetable. Threeareredandtherestare green.Howmanyapplesare green? 3+?=5,5–3=? Grandmahasfiveflowers.How manycansheputinherredvase andhowmanyinherbluevase? 5=0+5,5=5+0 5=1+4,5=4+1 5=2+3,5=3+2 Bigger Unknown Smaller Unknown (Versionwith“more”): Juliehasthreemoreapplesthan Lucy.Lucyhastwoapples.How manyapplesdoesJuliehave? (Versionwith“fewer”): Lucyhas3fewerapplesthan Julie.Lucyhastwoapples.How manyapplesdoesJuliehave? 2+3=?,3+2=? (Versionwith“more”): Juliehasthreemoreapplesthan Lucy.Juliehasfiveapples.How manyapplesdoesLucyhave? (Versionwith“fewer”): Lucyhas3fewerapplesthan Julie.Juliehasfiveapples.How manyapplesdoesLucyhave? 5–3=?,?+3=5 6 AdaptedfromBoxes2–4ofMathematicsLearninginEarlyChildhood,NationalResearchCouncil(2009,pp.32–33). Thesetakeapartsituationscanbeusedtoshowallthedecompositionsofagivennumber.Theassociatedequations,whichhavethe totalontheleftoftheequalsign,helpchildrenunderstandthatthe=signdoesnotalwaysmeanmakesorresultsinbutalwaysdoes meanisthesamenumberas. 8 Eitheraddendcanbeunknown,sotherearethreevariationsoftheseproblemsituations.BothAddendsUnknownisaproductive extensionofthisbasicsituation,especiallyforsmallnumberslessthanorequalto10. 9 FortheBiggerUnknownorSmallerUnknownsituations,oneversiondirectsthecorrectoperation(theversionusingmoreforthe biggerunknownandusinglessforthesmallerunknown).Theotherversionsaremoredifficult. 7 PrepublicationVersion,April2013 CaliforniaDepartmentofEducation 150| Table 2. Common multiplication and division situations.10 GLOSSARY Equal Groups Arrays,11 Area12 Compare General Unknown Product Group Size Unknown (“Howmanyineachgroup?” Division) Number of Groups Unknown (“Howmanygroups?” Division) 3u6=? 3 u ? = 18 and 18 ÷ 3 = ? ? u 6 = 18 and 18 ÷ 6 = ? Thereare3bagswith6 plumsineachbag.How manyplumsarethereinall? Measurementexample.You need3lengthsofstring,each 6incheslong.Howmuch stringwillyouneed altogether? If18plumsareshared equallyinto3bags,thenhow manyplumswillbeineach bag? Measurementexample.You have18inchesofstring, whichyouwillcutinto3 equalpieces.Howlongwill eachpieceofstringbe? If18plumsaretobepacked 6toabag,thenhowmany bagsareneeded? Measurementexample.You have18inchesofstring, whichyouwillcutintopieces thatare6incheslong.How manypiecesofstringwillyou have? Thereare3rowsofapples with6applesineachrow. Howmanyapplesarethere? Areaexample.Whatisthe areaofa3cmby6cm rectangle? If18applesarearrangedinto 3equalrows,howmany appleswillbeineachrow? Areaexample.Arectangle hasarea18square centimeters.Ifonesideis3 cmlong,howlongisaside nexttoit? If18applesarearrangedinto equalrowsof6apples,how manyrowswilltherebe? Areaexample.Arectangle hasarea18square centimeters.Ifonesideis6 cmlong,howlongisaside nexttoit? Abluehatcosts$6.Aredhat costs3timesasmuchasthe bluehat.Howmuchdoesthe redhatcost? Measurementexample.A rubberbandis6cmlong. Howlongwilltherubber bandbewhenitisstretched tobe3timesaslong? Aredhatcosts$18andthat is3timesasmuchasablue hatcosts.Howmuchdoesa bluehatcost? Measurementexample.A rubberbandisstretchedto be18cmlongandthatis3 timesaslongasitwasat first.Howlongwasthe rubberbandatfirst? Aredhatcosts$18anda bluehatcosts$6.Howmany timesasmuchdoesthered hatcostasthebluehat? Measurementexample.A rubberbandwas6cmlongat first.Nowitisstretchedtobe 18cmlong.Howmanytimes aslongistherubberband nowasitwasatfirst? aub=? au?=pandpya=? ?ub=pandpyb=? 10 Thefirstexamplesineachcellareexamplesofdiscretethings.Theseareeasierforstudentsandshouldbegivenbefore themeasurementexamples. 11 Thelanguageinthearrayexamplesshowstheeasiestformofarrayproblems.Aharderformistousethetermsrows andcolumns:Theapplesinthegrocerywindowarein3rowsand6columns.Howmanyapplesareinthere?Bothforms arevaluable. 12 Areainvolvesarraysofsquaresthathavebeenpushedtogethersothattherearenogapsoroverlaps,soarray problemsincludetheseespeciallyimportantmeasurementsituations. PrepublicationVersion,April2013 CaliforniaDepartmentofEducation 151| GLOSSARY Table 3. The properties of operations. Herea,bandcstandforarbitrarynumbersinagivennumbersystem.Thepropertiesofoperations applytotherationalnumbersystem,therealnumbersystem,andthecomplexnumbersystem. Associativepropertyofaddition (a+b)+c=a+(b+c) Commutativepropertyofaddition a+b=b+a Additiveidentitypropertyof0 a+0=0+a=a Existenceofadditiveinverses Foreveryathereexists–asothata+(–a)=(–a)+a=0. Associativepropertyofmultiplication (aub)uc=au(buc) Commutativepropertyofmultiplication aub=bua Multiplicativeidentitypropertyof1 au1=1ua=a Existenceofmultiplicativeinverses Foreveryaz0thereexists1/asothatau1/a=1/aua=1. Distributivepropertyofmultiplicationover au(b+c)=aub+auc addition Table 4. The properties of equality. Herea,b,andcstandforarbitrarynumbersintherational,real,orcomplexnumbersystems. Reflexivepropertyofequality a=a Symmetricpropertyofequality Ifa=b,thenb=a. Transitivepropertyofequality Ifa=bandb=c,thena=c. Additionpropertyofequality Ifa=b,thena+c=b+c. Subtractionpropertyofequality Ifa=b,thena–c=b–c. Multiplicationpropertyofequality Ifa=b,thenauc=buc. Divisionpropertyofequality Ifa=bandcz0,thenayc=byc. Substitutionpropertyofequality Ifa=b,thenbmaybesubstitutedforainanyexpressioncontaininga. PrepublicationVersion,April2013 CaliforniaDepartmentofEducation 152| GLOSSARY Table 5. The properties of inequality. Herea,b,andcstandforarbitrarynumbersintherationalorrealnumbersystems. Exactlyoneofthefollowingistrue:a<b,a=b,a>b. Ifa>bandb>cthena>c. Ifa>b,thenb<a. Ifa>b,then–a<–b. Ifa>b,thena±c>b±c. Ifa>bandc>0,thenauc>buc. Ifa>bandc<0,thenauc<buc. Ifa>bandc>0,thenayc>byc. Ifa>bandc<0,thenayc<byc. PrepublicationVersion,April2013 CaliforniaDepartmentofEducation 153|