Addition:MakingTens
Makingtensisanimportantstrategyfor
fluency.Studentsworkwithten-frames
(below).Theycombinedotstofillatenframe.Below,wemoved2dotsfrom5
tomakeaten.Theresultis10+3.
Wecanapplythe
combinationsof
tenstoaddother
numbers.In58+5,
wemightbreak
apart5into2+3
andthenaddthe2
58.
to58makingthenexttenwhichis60.
SubtractionUsingTenFrames
Wecanalsousetensforsubtraction.The
ten-framebelowshows14.Tosubtract
14-9,wecanbreak9into4and5.We
cansubtractthe4from14givingus10.
Then,5lessthan10is5.Eventually,this
willbecomeautomaticforstudents.
WorkingwithBaseTenBlocks
34
Basetenblocksareamathtoolthat
helpusbuildnumbers.Therodisequal
to10andthesinglecubeisequalto1.
AdditionwithBaseTenBlocks
58+5
Weadd
58is
5more
5tens
8ones
ones.
Wecombine
onestomake
anewten.
In58+5,wemakeanewtenfromtheones
(8+2).Thisleavesuswith6tensand3ones
leftover.So,58+5=63
SubtractionwithBaseTenBlocks
80–30
Infirstgrade,weworkwithtakingtensfrom
tens.Below,thereare8tens(80)andwe
takeaway3tens(30)leaving5tens(50).So,
80-30=50
HundredsChart
Thehundredschartisausefulmathtool.
Studentscanaddandsubtractonthe
hundredschart.
14+30=44
Astudentstartedat14andjumpeddown3
rowsof10(30)toequal44.
90–40=50
Astudentstartedat90andjumpedup4
rowsof10(40)toequal50.
AdditionandSubtractiononNumberLines
Numberlinesareusefulforaddingand
subtracting.Atfirst,studentswilljumpin
incrementsof1.Theywilldevelopmore
efficientstrategiesandjumpsastheir
numbersenseimproves.Thisexperience
developsmentalmathskillsandsupports
workwithalgorithms.Thesenumberlines
show58+7withjumpsof1,bybreaking7
apart,andonesinglejump.
Whensubtracting,wecancountbackfroma
numberorwecancountupfromone
numbertoanothertofindthedifference.
Thenumberlinesshowexamplesfor60-40.
Addition:PartialSums
Studentsmaybreaknumbersapartto
addtenswithtensandoneswithones.
Theyfind“parts”ofthesumandcan
thencombinetofindthetotalsum.
58+5=
58+5=
58+5=
50+(8+5)=
50+(8+5)=
50
8
8+5=13
50+13=63
50+13=63
50+13=63
Subtraction:PlaceValue
Studentsapplytheirknowledgeof
subtractingsingledigitnumbersand
placevaluetosubtractmultiplesof10.
50–20=30
5–2=3
5tens–2tens=3tens
50-20=30
Addition:Properties
Studentscanaddnumbersbyusingthe
propertiesofadditiontorearrangeor
groupthenumbers.
4+8+6=
Commutative
Associative
Property
Property
4+6+8=
rearrangingthe
groupingthe
numbers
numbers
10+8=18
8+6=6+8
4+6+8
=
Developing
Computational
Fluency
Grade1
ElementaryMathematicsOffice
HowardCountyPublicSchoolSystem
Thisbrochurehighlightssomeofthemethodsfor
developingcomputationalfluency.Formore
informationaboutcomputationandelementary
mathematicsvisit
https://hcpss.instructure.com/courses/32029/pages/
grade-1-star-mathematics-overview