Upload
vannhi
View
212
Download
0
Embed Size (px)
Citation preview
Atthecompletionofthisunit,youwillbeableto:
multiplyanddividefractionsbywholenumbers,otherfractions,andmixednumbersusingmodels,drawingsandsymbols
estimateproductsandquotientsofwholenumbers,fractionsandmixednumbers
solveandcreateproblemsusingfractionoperations
calculatethevalueofexpressionsinvolvingfractions,usingtheproperorderofoperations
communicateclearlyaboutfractionoperations
Unit6:FractionOperations
Whatfractionofeachglassisfull?Assumethatthefullestglassisequalto1.
Howdothefractionscomparetoeachother?
Whichfractionswithadenominatorof8canberenamedinlowerterms?
Whichfractionscanbeaddedtogiveasumof1?
Whichfractionshaveadifferenceof1/2?
Theequation2+2/3=22/3tellsthesumoftheareasoftwoofthecolours.Whichcolours?Howdoyouknow?
redandblue4reds(1/2each)=22blues(1/3each)=2/3
Ifayellowhexagonhasanareaof1unit,whatistheareaofeachblock?
a)aredblock 1/2unit
b)ablueblock 1/3unit
c)agreenblock 1/6unit
Whatfractionscanyouusetodescribethepatternblockdesign?
a)1+4/2(2)=3
b)2/33/6=1/6
c)37/6(11/6)=15/6
d)4/23/6=23/6=13/6or11/2
Writeequationswithfractionsand/ormixednumberstodescribethefollowingareas.Makesureyousolveyourequations.Showyourwork.
a)theyellowandredpartsb)howmuchmoreisbluethangreenc)howmuchmoreisyellowandredthangreenandblued)howmuchmoreisredthangreen
Createyourowndesignusingthefollowing:
1.yellow,red,blue,andgreenpatternblocks
2.atotalofeightblocks
3.atleast2yellowblocks
4.atleastoneblockofeachothercolour
5.writefractionsand/ormixednumberstodescribeeacharea.Showyourwork.
6.Gototwootherdesignsandwrite3fractionequations(addingorsubtracting)forthosedesigns.
Aim: I can use repeated addition to multiply fractions by whole numbers
Multiplying a Whole Number by a Fraction
What does the fraction 3/4 mean?
How could you use a rectangle to model 3/4?
How could you use fraction strips to model 3/4?
How could you model 3/4 on a number line?
How could you model 3/4 using a grid and counters?
the number of parts being named
the number of equal parts into which the whole is divided
Fraction review:What is a denominator?
What is a numerator?
Think about it
Jana is having a party. After a few hours, she notices that 6 pitchers are each only 3/8 full. She decides to combine the leftovers to use few pitchers.
How many pitchers will the leftover lemonade fill completely?
Use a model to represent 8/8 of a pitcher.
Use this model to represent lemonade from the 6 partially full pitchers. Write as both an improper fraction and a mixed number.
When you add the above fractions, you will end up with 18/8 or 2 2/8 or 2 1/4.
Why could you write
3/8+ 3/8 + 3/8 + 3/8 +3/8 + 3/8 or 6 x 3/8 to describe the total amount of lemonade in the pitchers?
Draw 4 grids that are 6 by 2 in your notebook and show how you can represent 4 sets of 5/6.
How could you calculate 4 x 5/6 using grids and counters?Represent the answer as an improper fraction and as a mixed number.
4 x 5 = 4 x 5 = 20 6 6 6
or 3 2/6 or 3 1/3
You can also move the chips from the last grid in to fill the other three grids. This will show you your mixed number.
4 x 5/6 is four sets of 5/6
3 x 2 = 3 x 2 = 6 3 3 3
= 2
How can you calculate 3 x 2/3 using fraction strips? Write the product as an improper fraction and as a whole or mixed number.
5 x 3 = 5 x 3 = 15 = 7 1/2 2 2 2
How could you calculate 5 x 3/2 using a number line? Write the product as an improper fraction and as a whole or mixed number.
0 1 2 3 4 5 6 7 8 9 10
0 1 2 3 4 5 6 7 8 9 10
3/2 3/2 3/2 3/2 3/2
Jenniferpours2/3ofacupofwaterintoapotandrepeatsthis7times.Howmanycupsofwater,intotal,doesshepourintothepot?Useoneofthestrategies(grid,fractionstrips,ornumberline)toshowyouranswer.Writeitasamixednumber.
Yourassignment:Pages49and50#3,5,6,8,13and16
About1/10ofCanadianswhoare12andolderdownhillski.About2/5oftheseskiersarebetween
theagesof12and14.
WhatfractionoftheCanadianpopulationbetweentheagesof12and14aredownhillskiers?
IdentifytheKeyInformation
1/10Canadiansolderthan12ski.
2/5ofthe1/10areaged1214.
Whatfractionofthe1/10areaged1214?
MakeaPlan
Multiply2/5by1/10.
CarryoutthePlan
Thisiswhatwearelearningtoday!
1. Drawagridthatrepresentsthedenominator(5x10).
3.Thisrectangleis .
Itsareais2x1squaresoutofthetotal5x10squares.
4.
1/25Canadiansbetweentheagesof12and14downhillski.
Things to ponder...1.Howdoesthismodelshowbothand?
2.Howcanyouuseamodeltodeterminethenumeratoranddenominatorofaproduct?
3.Suggestapossibleprocedureformultiplyingtwofractionslessthan1.Whydoesthiswork?
To multiply 2 fractions less than one you can:
A.Drawthegrid.
B.Multiplythenumeratorsanddenominators.
e.g.
GridMethod
1.Drawagridwiththedimensionsofthedenominators.
2.Fillthegridwitharectanglethedimensionsofthenumerators.
3.Rewritethefractionasthe .
4.Writeinlowestterms.
e.g.
Multiplication
1.Multiplythenumeratorsanddenominators.
2.Rewriteinlowestterms.
Jacksonisawakefrom2/3oftheday.Hespends5/8ofthattimeathome.WhatfractionofthedayisJacksonawakeat
home?
TheGrade8classraised2/5ofthemoneyto
supporttheschool'swinterproduction.TheGrade8boysraised2/3oftheGrade8
money.Whatfractionofthewholeproductionfunddidthegrade8boysraise?
Aboriginalpeoplesmakeupabout3/20ofthepopulationofManitoba.Ofthose,onlyabout1/3areunder15.WhatfractionofManitoba'stotalpopulationismadeupof
Aboriginalpeoplesunder15?
OnetwentiethofManitoba'spopulationismadeupofAboriginalpeoplesundertheageof15.
Thegrade8boysraisedfourfifteenthsoftheproductionfund.
Jacksonisawakeforfivetwelfthsoftheday.
More Practice:
pg 54
1b, 2, 3, 4bc, 5, 6, 7, 8, 11 a
Aim: I can multiply mixed numbers and improper fractions.
Fraction Products and Multiplying Fractions Greater than 1
Thinkofastrategyyoumightusetosolvethisproblem?
A large tub of popcorn holds 2 1/2 times as much as a smaller tub. Aaron has 1 1/2 large tubs.He is pouring the popcorn into smaller tubs to give to friends.
How many small tubs will his popcorn fill?
smaller large
Thinkaboutwhywewouldsetupthemodelinthisway.Howdothenumbersinthisproblemhelpyoudecidehowlargetomaketherectangles?
AreaofAis1x2=2squareunits
AreaofBis1x1/2=1/2squareunit
AreaofCis1/2x2=1squareunit
AreaofDis1/2x1/2=1/4squareunit
Thetotalareais
2+1/2+1+1/4=33/4squareunitsHecouldfill33/4smalltubs.
Onestrategymightbetouseanareamodel.Weknowthisisamultiplicationproblembecausewehave11/2groupsof21/2.
AB
C D
1
1/2
2 1/2
Another strategy might be to set up a procedure.
Turn the problem into an equation. 1 1/2 groups of 2 1/2 becomes 1 1/2 x 2 1/2. Having a mixed number can make it difficult to solve, so turn each mixed number into an improper fraction. 1 1/2 is the same as 3/2, and 2 1/2 is the same as 5/2. By doing this, it will be easier to multiply.
3 5 2 2
x = 3 x 52 x 2
15 4
= = 3 34
Multiply the renamed fractions just like you would multiply fractions less than one.
2 1/2 x 3 1/3 = (2 x 3) + (2 x 1/3) + (1/2 x 3) + (1/2 x 1/3) = 6 + 2/3 + 3/2 + 1/6(make 6 common = 6 + 4/6 + 1 3/6 + 1/6denominator) = 7 + 8/6 or 8 2/6 or 8 1/3
Multiply 2 1/2 x 3 1/3 using area grids.
3 1/3
2
1/2
( 3 x 2)
3 x 1/2
1/3 x 2
1/3 x 1/2
Tomultiply21/2x31/3asaprocedure,youcandothefollowing:
212
52
3 13
=
= 103
52
10x 52 3
x=3 x10
=506 68 8= 3
2 1
Now,try5/8x61/2usingbothagridandaproceduretocalculate.Doyoucomeupwiththesameanswerforboth?
Usethestrategiesdiscussedinthislessontofindtheanswertotheproblem.
Miriam is making 3 1/2 dozen cookies. If 2/7 of the cookies have icing, how many dozen cookies have icing?
Today'sAssignment:
Pages61and62
#s5,7,8,10,12,14&16
Aim: I can use a sharing model to represent the quotient of a fraction divided by a whole number.
Dividing Fractions by Whole Numbers
Fourtenthsofthepossibledonorsstillhavetobecalled.Twoofthestudentsaregoingtosharethejob.
Whatfractionofallthepossibledonorswilleachstudentbecalling?
How
Thesameasthenumeratorofthefraction
Howdoyouknowhowmanycounterstouse?
Thenumberofsquaresisthesameasthedenominator.
Tofindthesolution,weneedtodividethefractionbyawholenumber.
Howdoweknowhowmanysquarestouseinthegridofthefraction?
4 10
2
4102=
210
WhenIdivideby2,Iseparatethemodelinto2equalgroups.WhenImultiplyby2,Iaddthemodel2times.
Whatdoyoudodifferentlytothegridmodelofthefractionwhenyoudivideitbyawholenumberthanwhenyoumultiplyitbyawholenumber?
4 10
2
Createagridandusethisstrategytosolvethisproblem.Remember,ifyouhave1/3,youaredividingby3.
Allison had art class 9 out of the 20 school days last month. She worked with a partner about 1/3 of the time. For what fraction of the school days did she work with a partner in art?
9 out of 20 is 9 209203 = =
320
9 3 20
Allison worked with a partner for 3 of the 20 days.
How do we divide a fraction if the numerator is not divisible by the whole number?
2/3 of a room still has to be tiled. Three workers are going to share the job. What fraction of the room will each worker tile if they all work at the same rate?
23 3 = 23
32 cannot be divided by 3 evenly. Since we are dividing fractions, we cannot have a decimal number. We need to find an equivalent fraction to 2/3 that can be divided by 3. An equivalent fraction to 2/3 would be 6/9. 6/9 can be divided by 3. 6__3
9 = 2
9
Assignment:Page71#s4,6,7,9and10
Dividing Fractions Using a Related Multiplication
Aim: Divide fractions using a related Multiplication.
Allison has 2 large cans of paint. Nikita has 7/8 of a large can of paint. Each student is pouring paint into small cans that hold 1/3 as much as the large ones.
How many small cans of paint will each student fill?
Allison Allison Nikita
Thinkofastrategyyoumightusetosolvethisproblem?
TofindouthowmanysmallcansIcanfill,Icandivide2by1/3
Ineededtodivide2by1/3toseehowmanysmallcans(1/3thesizeofthebigcans)wouldbefilledby2largecans.
2 = 2x
Thisiscalledtakingthereciprocal.Thereciprocalisthefractionthatresultsfromswitchingthenumeratorandthedenominatorofthefractionontherightsideoftheequation.
Flip rig
ht sid
e frac
tion
and Mu
ltiply
Ineededtodivide7/8by1/3toseehowmanysmallcanswouldbefilledbya7/8fulllargecan.
TofindouthowmanysmallcansIcanfill,Icandivide7/8by1/3
= x
Wecannowmultiplystraightacross
= =
Rahulhas2/3ofacontaineroftrailmix.Heisfillingsnackpacksthateachuseabout1/5ofacontainer.HowmanysnackcanRahulmake?
Trythiswithapartner
1) What is your initial amount?
2) What is the amount they are being divided into?
3) What is your equation going to look like?
4) Which equation do we flip?
Rahulhas2/3ofacontaineroftrailmix.Heisfillingsnackpacksthateachuseabout1/5ofacontainer.HowmanysnackcanRahulmake?
Thisisreallyaskingwhatis2/3dividedby1/5
HomeworkPg.8586#2,3af,6ad,9a,13
Attachments
MSOfficePNG.png
MSOfficePNG12818.png
MSOfficePNG30212.png
SMART Notebook
SMART Notebook
SMART Notebook
OrderofOperations2.10
Learner OutcomeUseorderofoperationsincalculationsinvolvingfractions
TheOrderofThings...
WithaPartner,try:(6+9) X (8 - 3) 25 + 7 - 4 X 2 =
Brackets
= 15 X 5 25 + 7 - 4 X 2
Multiply and Divide
= 75 25 + 7 - 4 X 2 Multiply and Divide
75 25 + 7 - 4 X 2 Multiply and Divide
= 3 + 7 - 8 Add and Subtract
= 3 + 7 - 8
Add and Subtract= 10 - 8
Add and Subtract= 2
NowTry...
EquililentFraction
Reciprical
Reduce
Target1Game
Thegoalistocreateanequationwhosesolutionisasclosetooneaspossible
Eachgroupcutsoutonefractionsheetandoneoperation
sheet
Ineachroundbothpartnerstake3
fractioncardsandtwooperationcards
Rearrangeyourfractionssotheyareasclosttoone
aspossible
ThepersonclosesttoonewinsthatroundThefirsttofiveroundswins!!
Solve
YourAssignment
Page90#1,3,6,7a13
Important Terms
Fraction: One number written over another. The operation is to divide the top the bottom
Numerator: Top number in a fraction
Denominator: Bottom number in a fraction
Mixed Fraction: Mix between a whole number and a fraction
Improper fraction: When the numerator is larger than the denominator
Chapter 2: Fractions January 26, 2011 3:41 PM
Chapter 2 Page 1
"How Many Times Does the bottom number fit into the top?" This will be your whole number (left of your fraction)
1.
Find what's left over (Whole number times bottom number, subtracted from original top number). Put that number as a fraction over the original denominator.
2.
Fraction Conversation NotesJanuary 31, 2011 8:28 AM
Chapter 2 Page 2
Chapter 2 Page 3
Chapter 2 Page 4
January 31, 2011 5:40 PM
Chapter 2 Page 5
fractionaction
Inserted from:
Fraction ActionJanuary 31, 2011 5:24 PM
Chapter 2 Page 6
file://S:/XEROX-SCAN/fractionaction.PDF
fractionactionans Chapter 2 Page 7
fractionactionans
Inserted from:
Chapter 2 Page 8
file://S:/XEROX-SCAN/fractionactionans.PDF
Chapter 2 Page 9
Fraction DiagramsJanuary 31, 2011 5:36 PM
Chapter 2 Page 10
Chapter 2 Page 11
February 3, 2011 9:00 AM
Chapter 2 Page 12
Chapter 2 Page 13
Chapter 2 Page 14
Chapter 2 Page 15
2.1
Inserted from:
2.1February-06-11 11:32 AM
Chapter 2 Page 16
file://S:/Grade 8/GREVEBR/Math 8/CH 2/Scanning/2.1.PDF
Chapter 2 Page 17
2.2
Inserted from:
2.2February-06-11 11:32 AM
Chapter 2 Page 18
file://S:/Grade 8/GREVEBR/Math 8/CH 2/Scanning/2.2.PDF
Chapter 2 Page 19
2.3
Inserted from:
2.3February-06-11 11:32 AM
Chapter 2 Page 20
file://S:/Grade 8/GREVEBR/Math 8/CH 2/Scanning/2.3.PDF
Chapter 2 Page 21
2.4
Inserted from:
2.4February-06-11 11:32 AM
Chapter 2 Page 22
file://S:/Grade 8/GREVEBR/Math 8/CH 2/Scanning/2.4.PDF
Chapter 2 Page 23
2.5
Inserted from:
2.5February-06-11 11:32 AM
Chapter 2 Page 24
file://S:/Grade 8/GREVEBR/Math 8/CH 2/Scanning/2.5.PDF
Chapter 2 Page 25
February 9, 2011 9:11 AM
Chapter 2 Page 26
Chapter 2 Page 27
Chapter 2 Page 28
Just like multiplying, convert all mixed fractions to improper fractions
Take the reciprocal of the fraction you are dividing by and change the division sign to multiplication
Top times top, bottom times bottom. Convert to a mixed fraction and reduce Done :)
Dividing Mixed FractionsFebruary-09-11 7:32 PM
Chapter 2 Page 29
Chapter 2 Page 30
Always Use BEDMAS to determine order of operations:
B - BracketsE - ExponentsD - Division M - Multiplication A - AdditionS - Subtraction
Order of OperationsFebruary-09-11 7:39 PM
Chapter 2 Page 31
Chapter 2 Page 32
Chapter 2 Page 33
Chapter 2 Page 34
Chapter 2 Page 35
Chapter 2 Page 36
Chapter 2 Page 37
Chapter 2 Page 38
With a Partner:Cut out all fraction cards1.Place cards face down on a desk2.Each partner takes 3 fraction cards and 2 operation cards3.Each partner gets 1 set of brackets4.The goal is to arrange your fraction and operation cards to end up with an answer as close to 1 as possible
5.
Each win is worth 1 point, first to 5 points wins!6.
Math Game: Target 1February 11, 2011 8:51 AM
Chapter 2 Page 39
frac1
Inserted from:
February 17, 2011 9:03 AM
Chapter 2 Page 40
file://S:/XEROX-SCAN/frac1.PDF
frac2 Chapter 2 Page 41
frac2
Inserted from:
Chapter 2 Page 42
file://S:/XEROX-SCAN/frac2.PDF
Chapter 2 Page 43
Chapter 2 Page 44
introPage 1Page 2Page 3
21Page 1Page 2Page 3Page 4Page 5Page 6
22Page 1Page 2Page 3Page 4Page 5Page 6
25Page 1Page 2Page 3Page 4
26Page 1Page 2Page 3Page 4
29Page 1Page 2Page 3Page 4Attachments Page 1
30Page 1Page 2Page 3Page 4
Chapter 2