Fractions
Short Description
m...
Description
Fractions
H SERIES
Fractions
Curriculum Ready ACMNA: 152, 153, 154, 155
www.mathletics.com
Copyright © 2009 3P Learning. All rights reserved. First edition printed 2009 in Australia. A catalogue record for this book is available from 3P Learning Ltd.
ISBN
978-1-921861-40-6
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Fracons allow us to split things into smaller equal sized amounts. Write down two occasions where you have had to split something up evenly between family members or friends. Describe how you made sure this was done fairly each me.
is Give th
Q
a go!
For one parcular school: There are 256 students in Year 7. The Year 8, 9 and 10 groups all have half the number of students than the year just below them. 10 groups How many students are there at this school in Years 7 to 10?
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1
How does does it work ?
Fractions
Proper fractions Proper fracons represent represent parts of a whole number or object. 1 2
numerator denominator
number of equal parts you have total number of equal parts
The numerator is always smaller than or equal to the denominator in proper fracons. Let’s look at some equally sized shaded shapes. (i) Write a fracon fracon for for the shaded parts of the squares below: below:
Split into 2 equal parts
1 whole square
Split into 3 eq equa uall pa part rtss
Spli Sp litt in into to 4 equal parts
The number of equal parts shaded 1 = 1 1
1 2
2 3
2 4
The total number of equal parts
Larger denominator = smaller equal parts
(ii) Shade these to match match the fracon: 3 8
5 12
Shaded parts Total equal parts
(iii) Include at least two half-shapes half-shapes when shading these to match the fracon: 5 8
16 25
Two halves = 1 whole
2
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How does it work ?
Your Turn
Fractions
Proper fractions 1
2
What fracon of these equal-sized shapes have been shaded? a
b
c
d
e
f
g
h
Shade these to match the given fracon: a
3
5 12
b
8 8
3 7
c
d
11 16
e
4 10
e
1 4
Shade these to match the given fracon, including at least one pair of half-shapes: a
9 25
b
3 10
5 6
c
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d
7 10
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How does it work ?
Your Turn
Fractions P R OP ER F R
A
Proper fractions 4
Draw and shade diagrams with equal sized shapes to represent each of these fracons: (i) Shading whole shapes only. (ii) Including at least one pair of half-shaded shapes. 3 5
a
c
4
4
2 9
b
(i)
(i)
(ii)
(ii)
5 8
4 7
d
(i)
(i)
(ii)
(ii)
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C T
5
I O N
... P ..../...../ 2 0
S N O
R I O T P C E A R F R
S
How does it work ?
Fractions
Equivalent proper fractions These are fracons with dierent numbers that represent the same amount. For example, two tness teams do three sessions of training in the same park. Session 1: Grouped in pairs
Session 2: In groups of four
Session 3: Grouped as a whole team
1 2
2 4
4 8
Fracon of training groups wearing striped (or plain) shirts in each session. The groups change size but the total number of people training remains the same `
4 2 1 = = = Equivalent fracons 8 4 2
We nd equivalent fracons by dividing/mulplying the numerator and denominator by the same number. Write an equivalent fracon for each of these using the mulplicaon or division given in square brackets (i) 3 6# 3 @ (ii) 12 6' 4 @ 5 32 3#3 9 12 ' 4 3 = = 15 32 ' 4 8 5#3 `
3 and 9 = equivalent fracons 5 15
`
12 and 3 = equivalent fracons 32 8
Simplify these fracons by dividing the numerator and denominator by the highest common factor (HCF)
Simplify = Find the smallest equivalent fracon.
(i)
3 9
(ii) 18 24
HCF for 3 and 9 is: 3
HCF: the largest number that divides into both exactly
HCF for 18 and 24 is: 6
`
3 '3 1 = 9 '3 3
`
18 ' 6 3 = 24 ' 6 4
`
1 is the simplest equivalent fracon to 3 3 9
`
3 is the simplest equivalent fracon to 18 24 4
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How does it work ?
Your Turn
Fractions
Equivalent proper fractions 1
Write the equivalent fracons represented by these equally-sized shaded areas: a
b
=
2
3
a
1 6# 5 @ 4
b
8 6' 2 @ 10
c
3 6# 3 @ 5
d
12 6' 6 @ 24
6
=
=
Simplify these fracons by dividing the numerator and denominator by the highest common factor (HCF). 16 20
b
8 32
b
16 24
Simplify these two fracons. a
5
=
Write an equivalent fracon for each of these using the mulplicaon or division given in square brackets:
a
4
=
14 21
Are the fracons 14 and 16 from queson 4 equivalent fracons? Briey explain your answer. 21 24
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Fractons Mathletics
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How does it work ?
Your Turn
Fractions
Equivalent proper fractions 6
Match the pair of equivalent fracons below by joining them with a straight line. Solve the puzzle by matching the leer with the number each straight line passes through. T P RO L E N P E V A R I U F Q R E A
2 5
10 35
27 72
.... / ..... / 2 0 .. .
S
4 5
S
I
T
C
A
R F R E
8 12
6 15 6 24
1 4 8 14
1 2
5 15
6 30 1 5
2 3 4 7
1 3
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8 10
12 16
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Q
U
I V
A P L O E R N P T
2 7
15 30
I
O
N
O
3 4
3 8
T
N
6 10
3 5
C
7
How does it work ?
Fractions
Improper fractions and mixed numerals An improper fracon has a bigger numerator (top) than denominator (boom) 3 2
5 4
Improper fracons numerator 2 denominator
2 means
‘bigger than’
Mixed numerals have a whole number and a proper fracon. 11 2
Mixed numerals 11 4 A ‘mix’ of whole numbers and proper fracons.
Mixed numerals are simplied improper fracons. Simplify these Improper fracons to mixed numerals (i)
5 3
5 = 5 '3 3
numerator = numerator denominator
' denominator
= 1 r 2 remainder
2 = 1 3 Whole number answer (ii) 14 4
same denominator
14 7 = = 7 ' 2 Simplify if possible 4 2 = 3 r 1 remainder
1 = 3 2 Whole number answer
same simplied denominator
Mixed numerals to improper fracons +
(i) 1 2 3
2 3 # 1+ 2 = 3 3
1 #
=
(ii) 2 1 5
same denominator
+
1 5 #2+1 = 5 5
2 #
=
8
5 3
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11 5
same denominator
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picture form
How does it work ?
Your Turn
Fractions
Improper fractions and mixed numerals 1
Write the mixed numerals represented by these shaded diagrams: a
b
=
=
c
d
=
=
Make sure you write the fracon in simplest form where possible.
f
e
=
= B E L R A R S
E U M U M N N
D D E
2
a
3
b
14 3
M
c
23 2
D D N
N A
A
I
P R O P E E R R
0... 2 / . . . .. . / F I I .. R T . A T C F C R A
S S N N O O
15 9
b
21 14
c
18 16
c
44 5
Write the equivalent improper fracon for these mixed numerals. a
5
12 5
I M
Write these fracons in simplest form rst, then change to the mixed numerals. a
4
E X X I
Simplify these improper fracons by wring them as mixed numerals.
11 2
b
23 4
Write the equivalent improper fracon for these mixed numerals aer rst simplifying the fracon parts. a
4 2 12
b
2 6 24
c
Fracons Mathletics Passport
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25 24 72
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M
How does it work ?
Fractions
Fractions on the number line Proper fracons represent values between 0 and 1 on a number line. number of equal steps taken between 0 and 1 total number of equal steps between 0 and 1
1 2
Mark equal-sized steps matching the denominator between 0 and 1, then plot the fracon using the numerator. Display the fracons 1 , 3 and 2 on these number lines: 2 5 3 3 steps taken
1 step taken
1 = 2
3 = 5
1
0
2 equal steps between 0 and 1
2 steps taken
0
2 = 3
1
0
5 equal steps between 0 and 1
1
3 equal steps between 0 and 1
For mixed numerals, plot the fracon between the given whole number and the next whole number. number of equal steps towards the next whole number ‘4’ total number of equal steps between ‘3’ and the next whole number ‘4’
31 2
Start from this whole number
Display and read these fracons on a number line: Mixed numerals
(i) 4 1 2
(ii) 2 2 5
1 step taken towards 5 Start
1 2
4
2 steps taken towards 3 Start
5
2 5
2
3
5 equal steps between 2 and 3
2 equal steps between 4 and 5
Improper fracons – simply change to the equivalent mixed numeral rst then show on the number line
(i) 7 = 2 1 3 3
(ii) 18 = 3 = 1 1 12 2 2
1 step taken towards 3
Start
1 3
2
1 step taken towards 2
Start
3
1
1 2
2
2 equal steps between 1 and 2
3 equal steps between 2 and 3
Write down the fracon displayed on these number lines (i)
1
0
2 steps taken towards 1 1
0
4 equal steps between 0 and 1
2 1 Simplest form = 4 2
10
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(ii)
3
(iii) 4
2 steps taken towards 4 4
3
3 equal steps between 3 and 4
32 3
4
5
4 steps taken towards 5 4
5
6 equal steps between 4 and 5
4 4 = 4 2 Simplest form 6 3
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How does it work ?
Your Turn
Fractions T HE N U M BER LIN E F R A S C N T O I I O T N C S A R O N I F E L R E B N M U N E H T N O
Fractions on the number line 1
What proper fracon do the following points on the number line represent? a
0
2
b
1
1
0
1
1
1 4
c
3 3
0
b
0
1
8 15
1
c
0
1
0
1
Write the mixed numeral and equivalent improper fracon for the dots ploed on these number lines: a
2
c
b
3
1
5
2
=
6
=
=
Display these improper fracons on the number line: a
27 = 10
b
2 6
1
Write and display the fracon of equal shapes shaded on a number line for these diagrams: a
5
0
b
0
4
c
0
Display these fracons on a number line: a
3
..../ ...../ 20 . ..
11 = 2
3
22 = 5
c
4
5
6
Display these on the number line aer changing to equivalent fracons in simplest form rst. a
42 = 15
1
b
=
63 = 18
2
=
3
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c
110 = 25
=
4
5
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How does it work ?
Fractions
Reciprocal fractions 2 5
Original fracon
5 2
swap
Reciprocal fracon
Write the reciprocal of these fracons (i)
(ii)
3 4
18 8
3 4
3 4
swap
4 3
Reciprocal fracon
18 9 = 8 4
9 4
swap
4 9
Reciprocal fracon
Simplied
For mixed numerals, change to an improper fracon rst then write the reciprocal. 7 2
31 2
Mixed numeral
7 2
2 7
swap
Reciprocal fracon
Improper fracon
Whole/mixed number examples: Always write as a fracon rst. Write the reciprocal of these 3 = 3 1
(i) 3
3 1
1 3
Reciprocal fracon
4 11
Reciprocal fracon
swap
Whole number as a fracon
3 (ii) 2 4
23 4
11 4
11 4
swap
Improper fracon
9 (iii) 4 15
4 9 15 Simplied fracon
43 5
23 5
23 5
swap
5 23
Reciprocal fracon
Improper fracon
We will see why we nd the reciprocal a lile later on in this booklet. It is used when dividing an amount by a fracon.
12
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Fractons Mathletics
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How does it work ?
Your Turn
Fractions L F RA C T C A O I R O P N I S C E
Reciprocal fractions 1
Write the reciprocal for these fracons:
R
3
4
R
4
3
.... / . N
S
a
2
6 19
d
c
12 18
d
O
15 4
.... / 2 0 ...
I T C A A R F L
6 10
b
14 8
25 10
1 5
b
1 9
c
2
d
4
21 3
b
32 5
c
15 9
Write the reciprocal of these mixed numerals aer rst wring as a fracon: a
6
c
Write the reciprocal of these mixed numerals: a
5
11 7
Write the reciprocal of these: a
4
b
C I P R O C
Write the reciprocal, then simplify these fracons: a
3
2 3
E
3 2 10
b
1 10 12
c
2 9 21
c
15 115
Write the reciprocal of these fracons as a simplied mixed numeral: a
10 48
b
12 66
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Where does it work ?
Fractions
Comparing fractions This is where we see which fracons are larger than others. 1 2
1 3
or
Write equivalent fracons by changing the denominators to their LCM. 1#3 2#3
3 6
2 6
or
Lowest Common Mulple (LCM) The smallest value that appears in both mes tables
1#2 3#2
Since they have the same denominator, now just compare their numerators. bigger
smaller 1
`
3 6
2
2 6
1 2
2
1 3
Compare the size of these fracons (i)
2 , 3 and 5 3 4 12
2#4 3#4
2 3
,
3 4
8 12
,
9 12
`
5 12
1
8 12
5 12
1
2 3
and
1
1
5 12
3#3 4 #3 9 12
LCM of denominators = 12
and
5 12 Compare numerators
3 4
Order fracons by size
If comparing improper fracons, use the same method but leave the answer as a mixed numeral. (ii)
11 and 13 4 5
11 # 5 4#5
11 4
,
13 5
55 20
,
52 20
`
14
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LCM of denominators = 20
13 # 4 5#4
55 20
2
52 20
Compare numerators
23 4
2
23 5
Write in simplest form
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Where does it work ?
Your Turn
Fractions
Comparing fractions 1
Compare the size of these fracons: a
2 and 1 5 3
b
3 and 5 4 7
NG F R R I A C A P T M I O O C N
1
2
Compare the size of the fracons in each of these groups:
S
2
S
a
3
3 , 1 and 11 5 2 20
b
9 , 2 and 5 12 3 6
1
N.
... / .... . / 2 0 .. .
3
C
O O I M T P C A A R R I F G N
Compare the size of these improper fracons: a
9 and 16 4 7
b
14 , 15 and 21 3 4 8
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Where does it work ?
Fractions
Adding and subtracting fractions with the same denominator +
1 4 one quarter
=
+
2 4
=
3 4
and
two quarters
equals
three quarters
=
-
2 3
1 3
-
two thirds
less
one third
1 3
= equals
one third
If the denominator (boom) is the same, just add or subtract the numerators (top). Simplify these fracons with the same denominator
(i)
2 5 + 9 9
2 5 2 5 + = + 9 9 9 =
(ii) 6 - 2 7 7
7 9
6 2 6 2 = 7 7 7 =
(iii) 2 + 5 3 3
=
answers in simplest form
3 1 4 3 1 4 - + = - + 5 5 5 5 =
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Simplify
Subtract/add the numerators only
6 5
1 = 1 5
16
Add the numerators only
7 3
1 = 2 3
(iv) 3 - 1 + 4 5 5 5
Subtract the numerators only
4 7
2 5 2 5 + = + 3 3 3
Always write
Add the numerators only
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Simplify
Where does it work ?
Your Turn
Fractions
Adding and subtracting fractions with the same denominator 1
Simplify these without the aid of a calculator: a
d
1 1 + 3 3
8 6 11 11
b
3 1 5 5
c
5 2 + 9 9
e
11 4 15 15
f
3 5 + 8 8 H T I W
E S A M E D T H E N
O
M
I N A
S
N
T
O
O R
I
T
C
2
3
D D
R
A
... . G . / .
F
I N ... / 2 0 G ... N A T C A R T S D
N I
a
1 4 + 2 2
b
8 2 5 5
c
2 5 + 3 3
d
10 1 4 4
e
11 4 + 7 7
f
15 8 2 2
U B
Simplify these without the aid of a calculator, remembering to write the answer in simplest form: a
4
A
Simplify these without the aid of a calculator:
11 5 4 4
b
13 19 + 6 6
c
9 13 + 8 8
Simplify these without the aid of a calculator: a
4 1 2 + + 9 9 9
b
20 10 4 3 3 3
c
1 1 1 + 2 2 2
d
1 4 2 + 5 5 5
e
8 4 6 - + 7 7 7
f
13 11 9 + 6 6 6
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Where does it work ?
Fractions
Adding and subtracting fractions with a different denominator +
1 4
+
one quarter
and
=
1 2 one half
=
?
equals
?
+
1#2 2 = 4 2#2
=
1 4
+
2 4
=
one quarter
and
two quarters
equals
3 4 three quarters
Simplify these expressions which have fracons with dierent denominators
(i)
2 1 + 3 5
For
`
Mulply top and boom by the number used to make the denominator equal to the LCM
(ii) 7 - 1 + 3 8 2 4
2 1 and 3 5
Denominators are dierent
2 1 2#5 1#3 + = + 3 5 3#5 5#3 =
10 3 + 15 15
Equivalent fracons with LCM denominators
=
10 + 3 15
Add the numerators only
=
13 15
For 7 , 1 and 3 8 2 4
Denominators are all dierent
7 1 3 7 1#4 3#2 - + = + 8 2 4 8 2#4 4#2 =
7 4 6 - + 8 8 8
=
7- 4+ 6 8
=
9 8
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The LCM of all the denominators is 8
Equivalent fracons with LCM in the denominators
Simplify the numerator
1 = 1 8
18
The LCM of the denominators is 15
Simplify to mixed numeral
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Where does it work ?
Your Turn
Fractions
Adding and subtracting fractions with a different denominator 1
Fill in the spaces for these calculaons: a
1 1 The LCM of the denominators is: + 3 6 `
1 1 1# + = 3 6 3#
=
+
+
b
4 1 The LCM of the denominators is: 7 5
1 6
`
1 6
=
=
=
2
5 1 5# = 7 5 7#
-
1#7 5#7
-
=
simplest form
simplest form
Simplify these without the aid of a calculator: a
1 1 + 3 2
b
5 1 6 2
c
2 1 5 4
d
1 3 + 6 4
e
6 2 7 3
f
3 3 + 5 8
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Where does it work ?
Your Turn
Fractions
Adding and subtracting fractions with a different denominator 3
Simplify these expressions without the aid of a calculator, remembering to write the answer in simplest form. a
1 4 + 2 5
b
13 3 8 5
S
N
THE D IF F T H E R E N
W I
O I T
T D
E
C A R
N O
I
M
F
G
N I T
..../ ...../ A 20 . . I. D D S N
C
A R T B U
20
c
1 3 1 + 2 8 4
d
3 3 3 + 5 10 4
e
2 1 5 - + 3 4 6
f
7 1 11 - + 12 3 24
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Fractons Mathletics
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D N A G
N A T O R
Where does it work ?
Your Turn
Fractions
Adding and subtracting fractions with a different denominator The same rules apply for quesons with a mix of whole numbers and fracons. Here are some examples: Simplify these expressions which have a mix of whole numbers and fracons (i) 3 + 1 4
3+ 1 = 3 1 4 4
Write the fracon aer the whole number
(ii) 1 - 2 5
1- 2 = 5 - 2 5 5 5
Write the whole number as a fracon wit h same denominator
= (iii) 4 - 2 7
3 5
Subtract the numerators only
4 - 2 = 28 - 2 7 7 7 =
Write the whole number as a fracon wit h same denominator
26 7
5 = 3 7
4
Simplify the fracon
Simplify these expressions: a
2+ 1 2
b
1+ 3 4
c
1- 2 3
d
1- 3 8
e
2- 3 5
f
4- 1 4
g
3- 5 3
h
5- 5 2
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Where does it work ?
Fractions
Multiplying and dividing fractions To mulply fracons, just remember: Mulply the numerators (top) and the denominators (boom) of = ‘ # ’
1 of 2 = 3 5
1 3
#
2 5
=
1#2 2 = 15 # 3 5
To divide an amount by a fracon, just remember: ip the second fracon then mulply
1 3
'
2 1 = 5 3
#
5 2
=
1#5 3#2
=
5 6
Change the ‘ ' ’ to a ‘ # ’
Only ip the second fracon
Remember: A ipped fracon is called the reciprocal fracon
Simplify these: We can use shaded diagrams to calculate the mulplicaon of two fracons (i)
2 of 4 3 5
Draw a grid using the denominators as the dimensions
3 5 4 2
3
Use the numerators to shade columns/rows
5 =
`
2 3
#
8 15
4 8 = 5 15
Write where they overlap as a fracon
If whole numbers are involved, write them as a fracon (ii) 28 ' 2 7
`
28 ' 2 7
7 = 28 # 2 =
28 1
=
196 2
=
98 1
#
7 2
Flip the second fracon and change sign to ‘ # ’ Write the whole number as a fracon
Simplify
= 98
22
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Fractons Mathletics
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Where does it work ?
Your Turn
Fractions
Multiplying and dividing fractions 1
Calculate these fracon mulplicaons by shading the given grids: a
1 of 3 5 4
b
2 of 4 3 7
3 5 7 4 `
c
`
2 of 4 = 3 7
1 of 3 = 5 4
4 of 4 5 5
d
2 of 3 5 8
5
5
5
`
8
4 of 4 = 5 5
`
2 of 3 = 5 8
= simplied
e
3 of 7 4 9
f
3 of 5 4 6
4
4
9 `
3 of 7 = 4 9
6 =
`
simplied
= simplied
Fractons Mathletics
3 of 5 = 4 6
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Where does it work ?
Your Turn
Fractions
Multiplying and dividing fractions 2
Simplify these without the aid of a calculator: a
1 2
c
` 23 j
#
2
24
1 3
psst: this is just
2 3
#
b
3 5
d
` 53 j
#
1 4
2
2 3
e
1 3
'
3 2
f
2 11
g
5 6
'4
h
3 4
'
1 4
'8
i
10 # 4 5
j
24 # 3 8
k
12 ' 3 5
l
2' 2 13
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Fractons Mathletics
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N D D A I N G I V Y I I P L T L D U M I ' N S G N O F I R T A C C A . T R. . . I F / . O . N . G . . / S N I 2 M 0 U D L . # T . . Y I I P V I L N G I N D D A
Where does it work ?
Your Turn
Fractions
Multiplying and dividing fractions 3
Simplify these without the aid of a calculator, remembering to write the answer in simplest form. 2
a
c
4
3 8
` 28 j
b
3 4
#
3 2
5 4
d
2 3
'
5 3
f
3 4
#
2 3
h
1 2
'4 '
'
e
9 10
g
2 5
'
#
8 5
3 6
#
1 3
Is 2 of 4 exactly the same as 2 3 6 3
'
#
1 psst: same as the others! 2
1 psst: work le to right! 2
12 ? Explain your answer. 8
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Where does it work ?
Fractions
Operations with mixed numerals Just change to improper fracons then use the same methods as shown earlier. Simplify these calculaons involving mixed numerals Addion and subtracon
(i) 1 2 + 2 1 3 6
1 2 + 2 1 = 5 + 13 3 6 3 6 =
10 13 + 6 6
=
23 6
5 = 3 6
Or just add the whole numbers and the fracons separately. 2 1 5 1+ 2 = 3 + = 3 6 6
Equivalent fracons with LCM denominators
Simplify to mixed numeral
4 1 - 1 1 = 21 - 3 5 2 5 2
(ii) 4 1 - 1 1 5 2
Change to improper fracons
=
42 15 10 10
=
27 10
= 2 7 10
Change to improper fracons
Equivalent fracons with LCM denominators
Simplify to mixed numeral
Mulplicaon and division
(iii) 1 3 4
#
21 3
13 4
#
21 = 7 3 4 =
#
7 3
49 12
Mulply tops and booms together
1 = 4 12 (iv) 1 1 6
'2
11 6
Remember 2 3 etc 2 = ,3 = , 1 1
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'2
Change to improper fracons
Simplify to mixed numeral
=
7 6
'
2 1
Change to improper fracons
=
7 6
#
1 2
Flip second fracon and change to mulply
=
7 12
Mulply numerators and denominators together
Fractons Mathletics
© 3P Learning Ltd
Where does it work ?
Your Turn
Fractions H O NS W IT M T I I X R A E E D P O N # +
Operations with mixed numerals
U
S L
M
E R
A
1
2
Simplify these addions and subtracons without the aid of a calculator: a
21 +42 4 3
b
21 -12 4 5
c
53 -21 5 2
d
31 +11 6 5
b
43 7
#
d
51 3
#
b
12 3
'3
d
51 2
'1
c
4 #1 2 5
13 4
#
31 2
S
.... O / .. P D E E ... / R X 2 0 .. T A I M . N O I H T I W S
M U N
# +
2
14 5
Simplify these divisions without the aid of a calculator: a
3 '2 1 2
c
22 5
'1
1 2
Fractons Mathletics
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L
A
Simplify these without the aid of a calculator: a
3
R E
2 3
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Where does it work ?
Your Turn
Fractions
Combining all the operations Earn yourself an awesome passport stamp by trying these trickier quesons without using a calculator. 1 63 1 Simplify + 7 5
1 #1 2
E O M *
psst: remember your order of operaons
E S W
A
*
*
.. A . W 2 0 / . . E . . S . . O ... / M
* E
2
Simplify 4 1 2
3
Simplify this shaded diagram into a single fracon. psst: write as fracons, then work le to right
'3
5 6
#
5 1 psst: work le to right… so do the division rst 3
+
#
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Fractons Mathletics
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What else can you do ?
Fractions
Fractions of an amount How many links are there in 2 of a chain made using a total of 20 links? 5
Simplied, this queson is just: Find 2 of 20 . 5 `
2 of 20 2 = 5 5
#
=
2 5
#
=
40 5
Remember: ‘of’ = ‘ # ’
20 20 1
= 8 `
2 of the 20 links = 8 links 5
Here are some quesons that calculate fracons of an amount. (i) Juliet lost 1 of the 116 songs she had downloaded when a computer virus infected the les. 4 How many songs were not aected by the virus? 1 of 116 songs 1 = 4 4
#
1 3 are gone, then remain. 4 4 3 So nding of 116 will get 4 the same answer. Try it!
If
116
=
1 116 + 4 1
=
116 4
= 29 `
(ii) How long is 7 of 1 hour? 10
116 - 29 = 87 songs not aected by the virus
7 7 = of 1 hour 10 10 of 60 minutes =
7 10
=
420 10
#
Answer the queson
Change to smaller units if possible
60 1
= 42 `
7 of 1 hour = 42 minutes 10
Fractons Mathletics
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Answer the queson
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What else can you do?
Your Turn
Fractions F R A CT I O NS
T N U O M A
Fractions of an amount 1
2
Calculate the amount for each of these, showing all working: a
1 of 20 5
b
3 of 32 4
c
2 of 24 3
d
5 of 42 6
. A 0 . . O M 2 / . U . . . . T N / . . S N O I . . A T C R F
N A F O
Calculate the amount for each of these by rst making the mixed numeral an improper fracon: psst: the answers will be bigger than the given whole number
3
a
2 1 of 4 2
b
1 4 of 15 5
c
3 2 of 14 7
d
4 2 of 36 3
Calculate these fracons of quanes, showing all working: a
How many hours is 3 of 1 day? 4
b
1 day = 24 hours
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How many grams is 3 of 2 kilograms? 10 1 kg = 1000 grams
Fractons Mathletics
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O F A N
What else can you do?
Your Turn
Fractions
Fractions of an amount 3
c
How long is 5 of 2 hours? 6
d
1 hour = 60 minutes
4
How far is 1 of 3 kilometres? 5 1 km = 1000 metres
In an orchestra of 60 musicians, 1 were in the brass secon. How many brass secon players were there? 5 psst: remember to include a statement answering the queson at the end
5
6
7
Krista and her team mates each receive 1 of a $900 prize for winning a compeon. 5 How much does Krista receive?
Hank bought 2 of the 28 towels that were on sale in a shop. How many towels were not bought by Hank? 7
The lead in one brand of HB pencil is 8 graphite. 11 How many grams of non-graphite material are there in this brand if every pencil contains 33 grams of lead?
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What else can you do?
Your Turn
Fractions
Fractions of an amount Here is what to do if you already have the fracon amount and need to nd the original whole amount. Amani used 250 g of one ingredient, which was 2 of the total ingredients used in the recipe she 5 was following. What is the total weight of ingredients used in this recipe?
A short-cut way is to mulply 250 g by the reciprocal. 5 250 g # = 625 g 2
8
9
10
32
2 of the total ingredients used Divide the amount by the numerator = 250 g 5 1 ` of the total ingredients = 250 g ' 2 5 = 125 grams Mulply answer by the denominator 5 (the total ingredients) ` = 125 g # 5 5 = 625 grams ` Total
weight of ingredients used in the recipe = 625 grams
The leer ‘e’ is used twenty one mes in this queson. If this is 1 of all the leers used to write 8 this queson, work out how many leers there are in total (show all working and check your amount by counng).
During a performance by Jolly Rob, 280 members of the audience found his jokes funny. If this was 4 of the total audience members at the performance, how many people were watching Jolly Rob? 7
By 3:00 pm, Juan had been waing 30 minutes for his bus to arrive. If this is 5 of the total me he 6 spent waing, at what me did his bus arrive?
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Fracons Mathletics Passport
© 3P Learning
What else can you do?
Fractions
Two amounts as a fraction Somemes we need to compare two amounts by wring one as a fracon of the other. For example, write 14 out of 36 as a fracon in simplest form 14 14 ' 2 = 36 36 ' 2 7 = 18 7 ` 14 out of 36 = 18
First amount Second ‘out of’ amount
Divide the amount by the HCF Simplest form
These examples show how both amounts must be in the same units before wring as a fracon. Write these amounts as fracons of one another in simplest form (i) All the boxes in the picture weigh a total of 40 kg. The box being carried is 2000 g. What fracon of the total weight is being carried? 40 kg = 40000 g `
2000 = the fracon of the total weight being carried 40000 =
1 kg = 1000 g ` the
Need both weights in the same smaller units
box being carried is
1 20
Simplify fracon
1 of the total weight Answer queson 20
(ii) What fracon of 2 1 hours is 15 minutes? 2 2 1 hours = 2 1 2 2
#
60 minutes
= 150 minutes 15 1 = 150 10
First smaller amount total amount `
1 hour = 60 minutes Need both mes in the same smaller units Simplify fracon
15 minutes is 1 of 2 1 hours 10 2
Answer queson
(iii) If one ream of paper contains 500 sheets, what fracon is 240 sheets out of 4 reams? 4 reams = 4 # 500 sheets = 2000 sheets 240 3 = 2000 25
First smaller amount total amount `
Need both amounts in the same smaller units Simplify
240 sheets is 3 of 4 reams 25
Fracons Mathletics Passport
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Answer queson
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What else can you do?
Your Turn
Fractions A S A T S F U N R
O
M
Two amounts as a fraction
A . . C . T . I / . O . . N . . / 2 0 T . . . W
A O
W
T
1
Write the rst amount as a fracon of the second for each of these in simplest form
N O I T C
5 out of 20
b
16 out of 22
c
35 marks out of a possible 40
d
2 hours of 1 day (1 day = 24 hours)
e
5 minutes of half-an-hour (1 hour = 60 minutes)
f
25 cents out of $2 ($1 = 100 cents)
g
300 seconds of 1 hour (1 hour = 3600 seconds)
h
23 days of March (31), April (30) and May (31)
A R F
A S A S
2
In a school of 800 students, 240 were in Year 7. What fracon of the school are Year 7 students?
3
Aer 100 test rolls, a die displayed the number 5 sixteen mes. What fracon of the rolls were 5?
4
Francesca red 27 arrows at a target and hit the bullseye 6 mes. What fracon of arrows missed the bullseye?
5
A biscuit recipe contained 500 g of our, 175 g of sugar and 125 g of buer. What fracon of the recipe is buer?
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Fractons Mathletics
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M
O U N T
a
O
A
What else can you do?
Fractions
Word problems with fractions While on a shopping trip, Xieng spent two hs of her money on clothes and one third on cosmecs. What fracon of her money did Xieng have le?
`
Fracon for all of Xieng ’s money ` Xieng
2 1 + = fracon of Xieng’s money spent on shopping 5 3 6 5 = + 15 11 Add the numerators together = 15 15 11 4 = 15 15 15 Fracon spent
Fracon of money Xieng has le
sll has 4 of her money aer shopping 15
Here are some other word problem examples (i) In a group of eighteen friends, one third are girls and one sixth of these girls have blonde hair. How many blonde girls are in the group? `
1 of 1 of 18 = number of blonde girls in the group 6 3 =
1 6
=
18 18
#
1 3
#
18 1
= 1 ` There
is 1 blonde girl in the group of friends.
(ii) During one night, possums ate two hs of the y ve fruits on a tree. If one eleventh of the eaten fruit grew back, how many fruits are now on the tree? 2 5
#
55 = Number of fruits eaten 110 5 = 22 =
1 11
#
22 = Number of fruits that grew back 22 11 = 2 =
` Number
of fruits now on the tree = 55 - 22 + 2 = 35 pieces of fruit
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What else can you do?
Your Turn
Fractions
Word problems with fractions 1
At a recent trivia night, one table of competors answered ve eighths of the y six quesons correctly. How many quesons did they get incorrect?
2
Co Tin usually takes approximately sixty and one quarter steps every minute when walking. How many steps does he expect to take when he exercises by walking for one and two third hours each day? S W O R N O D I P R T C O B A R L E F M H S T W I I W T S H M E F L R B A O C R T P I D O R N O W S
..../ ...../ 2 0 ..
.
3
A vegetable garden has one third carrots, one sixth pumpkins, one quarter herbs, and the rest are potato plants. How many potato plants are in this garden of eighty plants?
4
A class of twenty four students compared eye colours on a chart. Two thirds of the class had brown eyes, and three eighths of those brown-eyed students were boys. How many girls had brown eyes?
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Fractons Mathletics
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What else can you do?
Your Turn
Fractions
Word problems with fractions 5
For one parcular school: There are 256 students in Year 7. The Year 8, 9 and 10 groups all have half the number of students than the year just below them. How many students are there at this school in Years 7 to 10? ber Remem
me?
6
Five students in a class have a combined total of ninety proles added as friends on a web-based social network site. Three hs of the ninety proles are shared by all ve of the students. These shared proles represent one sixth of the total number of dierent proles added as friends by all the students in the class. How many dierent proles are linked to students from this class?
7
Five sevenths of the y six images used as backgrounds on Meagan’s touchpad were photos she took herself. Aer moving ve eighths of these photos to another computer, what fracon of the background images now are not photos taken by her?
Fractons Mathletics
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What else can you do?
Your Turn
Fractions
Reflection Time Reecng on the work covered within this booklet: 1
What useful skills have you gained by learning about fracons?
2
Write about one way you think you could apply fracons to a real life situaons.
3
38
If you discovered or learnt about any shortcuts to help with fracons or some other cool facts, jot them down here:
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Fracons Mathletics Passport
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