Multiplication of Fraction
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Transcript of Multiplication of Fraction
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Multiplicationof
FractionFor Namrita mam
By Mudit Saxena
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Multiplication of Fraction Here are some fraction
multiplication problems
Can you tell how tomultiply fraction fromthese examples?
4 1 4
5 7 35v !
6 4 24
5 10 50v !
21
10
7
5
3
2!v
3 5 15
4 12 48v !1 1 1
3 3 9v !
2 5 10
3 1 3
v !
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Multiplication Multiply numerator by numerator
And denominator by denominator
2 5 10
3 1 3v !
1 2 1 2
1 2 1 2
N N N N
D D D D
v
v !
v
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Try some. Multiply the following:
4 2
9 3v !
1 5
3 8v !
2 4
3 5v !
5 5
8 8v !
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Answers Multiply the following:
4 2 8
9 3 2v !
1 5 5
3 8 24v !
2 4 8
3 5 15v !
5 5 25
8 8 64v !
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Mixed Numbers Because of the order of operations,
Mixed numbers cannot be multiplied as is
Change mixed numbers to improper fractions, thenmultiply.
!v
8
51
5
23
17 135 8
v ! 17 13 2215 8 40
v !
221 40 5 with a remainder of 21
21540
z !
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Try some Change any whole or mixed numbers to
improper.
M
ultiply straight across. Simplify answers
21 7
5v !
18
5v !
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Answers Change any whole or mixed numbers to
improper.
M
ultiply straight across. Simplify answers
2 49 41 7 9
5 5 1 5 5v ! v ! !
1 1 8 8 38 1
5 5 1 5 5v ! v ! !
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u t p cat on o ract on y
Whole numbers
Considering the cake example
above, if you have a quarter ofthe cake and you multiply the
amount by three, then you get
three quarters as your answer.
We can write this numerically asfollows:
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C
ancellingReduce before you multiply
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Canceling Reducing before mutiplying is called
canceling.
ICK! Instead of that do the following:-
1120
300
35
12
32
25!v
25 12 25 12 5 5 4 3
32 35 32 35 8 4 7 5
v v v v
v ! !
v v v v
5 5 4 3 5 3 15
8 4 7 5 8 7 56
v v v v
! !
v v v v
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Canceling on paper Rules: One factor from
any numerator cancels
with like factor from thedenominator. 12
15
20
9
21
16vv
4
16 9
21 20v
15v
3
12
16 4
4
9
21 20v
15v
3
312
164
4
9
21 20v
15v
3
1
312
1
164
1
4
9
21v
1
20
15v
3
1
3
121
16 41
21 7
9v
3
4 120
15v
3
1
312
1
3
7!
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Try one Say --- goes into ____ this many times.
As you cross each number out and write what is
left after canceling above the number.
10
1
3
5v
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Answer Say --- goes into ____ this many times.
As you cross each number out and write what is
left after canceling above the number.
5
1
13 10
v
2
56
!
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Try one more Make whole and mixed numbers improper
Cancel if you can
Multiply Numerators and denominators straightacross.
Simplify
415
14
2
1421
10 vvv
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Answer Make whole and mixed numbers improper
Cancel if you can
Multiply Numerators and denominators straightacross.
Simplify
10 1 14
4 421 2 15
10 9 14 48
21 2 15 1
v v v
v v v !
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Thanks
for
watching