Answers to Practice Book exercises
1 Integers
F Exercise 1.1 Using negative numbers
1 5, 3, −1, −4, −5
2 a 09 00
b 13 00
3 a 2 °C
b −8 °C
c 6 degrees
4 0 °C
5 a −250 metres
b 150 metres
6 −14 °C
7 a 4
b −7
c 0
d 10
e 2
8 a −4
b −7
c −9
d −11
e −15
9 a −5
b 4
c −1
d −3
F Exercise 1.2 Adding and subtracting negative numbers
1 a 11
b −3
c 3
d −11
2 a −4
b 7
c 2
d −3
3 a −7
b −1
c 3
d 1
4 a 7
b 7
c 7
d 2
5 11 °C or −5 °C
6 10
7 first row 7, 4, 1; second row 3, 0, −3; third row 1, −2, −5
F Exercise 1.3 Multiples
1 a 9, 18, 27, 36, 45
b
12, 24, 36, 48, 60
2 a 24
b 24
3 a 32
b 20
c 44
4 a 42 or 49
b 48
c 42
5 a 119
b 105
6 a 15
b 24
c 30
c
20, 40, 60, 80, 100
d 26
d 28
7 60
8 a 501
b 1002 and 1503
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Cambridge Checkpoint Mathematics 7
1
Unit 1 Answers to Practice Book exercises
F Exercise 1.4 Factors and tests for divisibility
1 2, 3, 4, 6, 8, 12
2 a 1, 2, 4, 8
b 1, 2, 3, 4, 6, 12
c 1, 3, 7, 21
d 1, 17
b 1, 2, 5, 10
c 1, 2, 4, 8
d 1
e 1, 2, 4, 5, 8, 10, 20, 40
3 3, 6 and 36
4 31 and 37
5 1, 7, 13, 91
6 a 1, 3
7 There are many possible answers.
a For example: 9 or 25
b For example: 16 or 81
8 a 2571, 5427 and 8568
b 5427 and 8568
9 a 2884 and 2888
b 2885
c 2886
d 2888
e none
10 60
F Exercise 1.5 Prime numbers
1 8
2 47
3 83 and 89
4 Because a square number has a factor that is not 1 or itself.
5 a False; 2 is not odd
b False; 3, 5 and 7
c
6 a 3 + 5 + 17 or 5 + 7 + 13
b two
7 a 2 and 3
b 3
c 2 and 7
d 2, 3 and 5
8 a 3×7
b 2 × 11
c 5×7
d 3 × 17
True; 97
e 5 × 13
9 A prime number has just two factors, 1 and the number itself. Two prime numbers will have just 1 as a
common factor.
F Exercise 1.6 Squares and square roots
1 a 25
b 81
c 121
b 9 + 81
c 36 + 64
d 324
2 225
3 a 16 + 64
4 a 42 − 22 = 16 − 4 = 12 = 2 × 6; 52 − 32 = 25 − 9 = 16 = 2 × 8
b 72 − 52 = 2 × 12; 82 − 62 = 2 × 14
c 2 × 100 = 200
5 100 and 81
6 92 and 122 (81 and 144)
7 36
8 a 3
b 6
c 13
d 20
e 16
9 No. The value of the first is 5 and of the second is 7.
10 25
2
Cambridge Checkpoint Mathematics 7
Copyright Cambridge University Press 2012
Answers to Practice Book exercises
2 Sequences, expressions and formulae
F Exercise 2.1 Generating sequences (1)
1 a
b
c
i Add 2
i Add 3
i Subtract 4
ii
2 a
d
4, 7, 10
10, 21, 43
b 30, 25, 20
e 2, 11, 15.5
c 15, 14, 13
f 12, 12, 12
3 a
12, 18
b
24, 31, 45
c
39, 33, 15
4 a
finite
b
infinite
c
finite
ii
ii
iii
20, 22
17, 20
30, 26
iii
iii
30
32
10
d
23, 20, 11, 8, 5
5 No. The term after 6 is 17, but 6 + 3 = 9 and 6 × 2 = 12.
6 3
7 5
F Exercise 2.2 Generating sequences (2)
1 a
b 3, 6, 9, 12, 15
c Add 3.
d Three extra dots are added.
2 a
b
Pattern number
1
2
3
4
5
Number of squares
3
5
7
9
11
Pattern number
1
2
3
4
5
Number of blocks
5
7
9
11
13
c Add 2.
d i 17
ii
31
3 a
b
c Add 2.
d i 23
ii
43
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Cambridge Checkpoint Mathematics 7
1
Unit 2 Answers to Practice Book exercises
4 a
b 18
5 Oditi. 1 × 3 + 2 = 5, 2 × 3 + 2 = 8, 3 × 3 + 2 = 11 and 4 × 3 + 2 = 14
F Exercise 2.3 Representing simple functions
1 a input: 9; output: 8, 12
b input: 14; output: 3, 13
c input: 7, 20; output: 50
2 a input: 7, 6; output: 18
b input: 9, 8; output: 12
c input: 14, 26; output: 0.5
3 a +3
4
b ÷3
c ×7
Input
0
1
2
3
4
5
6
7
8
9 10
Output
0
1
2
3
4
5
6
7
8
9 10
5 Jake. 3 × 2 − 3 = 3, 5 × 2 − 3 = 7 and 9 × 2 − 3 = 15. Only two of Hassan’s work.
6
Input
1
2
3
Output
×2
1
3
5
–1
F Exercise 2.4 Constructing expressions
t
2
s
2
1 a t+4
b t−2
c t+5
d
2 a s+2
b 3s
c s−6
d
3 a x+2
b t – 15
c i + t years
d 2v
e $d
4 a 6n
b 5n + 1
c 7n − 2
d n÷4
e n ÷ 2 + 10
f n÷5–3
5 a $(a + c)
b $(a + 3c)
c $(4a + c)
d $(4a + 5c)
6 a 3(n + 2)
b n+2
c 4(n − 5)
d n −5
e vii
f ii
3
4
7 a iii
b i
c v
d iv
The unmatched expression is vi. Divide x by 5 and subtract from 4.
2
Cambridge Checkpoint Mathematics 7
4
Copyright Cambridge University Press 2012
Answers to Practice Book exercises Unit 2
F Exercise 2.5 Deriving and using formulae
1 a 16
g 13
b 117
h 9
2 a $80
b $144
c 20
i 12
d 25
j 18
e 60
k 0
f
l
7
11
3 a i The number of hours is equal to the number of days multiplied by 24.
ii H = 24D where H = number of hours and D = number of days
b 96 hours
4 a 20
b 36
5 a 3 hours
b 3.5 hours
6 a 100 minutes or 1 hour 40 minutes
b
225 minutes or 3 hours 45 minutes
7 4
8 Elite Cars
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Cambridge Checkpoint Mathematics 7
3
Answers to Practice Book exercises
3 Place value, ordering and rounding
F Exercise 3.1 Understanding decimals
1 a 442.5, 19.5, 140.1
b 312.01, 1.77, 5.69
c 12.776, 10.511
2 a 3 tenths
d 3 hundredths
b 3 units
e 3 tens
c 3 thousandths
f 3 ten thousandths
3 a 9 hundredths
b 6 units
c 3 tenths
4 9.15 kg
F Exercise 3.2 Multiplying and dividing by 10, 100 and 1000
1 a 280
e 5.37
i 710
m 11 500
b
f
j
n
c
g
k
o
2 a 51
b 60
c 1.27
d 0.184
e 200.2
3 a ÷
b ÷
c ×
d ÷
e ×
f ÷
4 a 10
b 10
c 100
d 100
e 1000
f 100
e 0.22
j 0.049
40
1.473
2.4
0.85
55
4400
1
3.37
d
h
l
p
2.2
3.9
0.013
0.0026
5 20
6 $0.225
7 0.0007
F Exercise 3.3 Ordering decimals
1 a 3.5
f 5.41
b 214.92
g 25.67
c 34.56
h 0.013
d 336.9
i 0.009
2 a <
e >
b >
f <
c <
g >
d >
h >
3 a 2.66, 4.41, 4.46, 4.49
d 5.199, 5.2, 5.212, 5.219
b 0.52, 0.59, 0.71, 0.77
e 42.4, 42.42, 42.441, 42.449
c 6.09, 6.9, 6.92, 6.97
f 9.04, 9.09, 9.7, 9.901, 9.99
4 Asafa Powell. Check for the third smallest ‘tenths’ value, then the smallest ‘hundredths’.
5 Any three from 6.461 to 6.470
F Exercise 3.4 Rounding
1 a 80
b 20
c 380
d 230
e 4380
f 6200
2 a 500
b 500
c 6400
d 5700
e 51 400
f 100
3 a 2000
b 6000
c 8000
d 2000
e 57 000
f 1000
4 No. 706 is 710 to the nearest 10 and 700 to the nearest 100.
5 a 9m
b 37 mm
c 377 km
d 303 kg
e 40 cm
6 a 0.1
b 5.6
c 6.8
d 12.3
e 98.8
f 0.1
7 Ahmad’s answer is correct to 1 d.p. Jake is wrong and Maha’s answer has not got 1 d.p.
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Cambridge Checkpoint Mathematics 7
1
Unit 3 Answers to Practice Book exercises
F Exercise 3.5 Adding and subtracting decimals
1 a 7.8
b 17.8
c 15.2
d 5.4
e 11.2
f 6.8
2 a 9.2
b 17.6
c 12.1
d 4.4
e 5.1
f 4.7
3 a 7.82
e 2.22
b 13.32
f 1.8(0)
c 30.18
g 19.08
d 122.17
h 39.04
4 a $4.10
b $0.90
5 a 6.55 m
b 1.45 m
6 a May
b 8.98 kg
7 a
3
7
.
6
2
2
8
.
5
3
6
6
.
1
5
+
b
–
8
4
.
5
6
2
8
.
5
9
5
5
.
9
7
F Exercise 3.6 Multiplying decimals
1 a 0.6
b 0.8
c 2.4
d 3
e 4.9
f 4.8
2 a 10.8
b 25.2
c 32.4
d 19.2
e 33.6
f 43.2
3 a 11.07
b 25.83
c 33.21
d 19.28
e 33.74
f 43.38
4 a 0.6
b 4
c 0.5
d 6
e 3.8
f 0.4, 2
F Exercise 3.7 Dividing decimals
1 a 3.2
b 4.1
c 0.4
d 0.8
e 2.4
f 1.4
2 a 3.12
b 2.34
c 1.01
d 1.03
e 2.71
f 1.31
3 a 2.89
b 3.17
c 0.76
d 3.83
e 3.94
f 3.06
4 $1.49
5 $1.26
6 a
4
2
8
.
2
8
.
5
1
b
6
3
1
.
5
7
4
.
1
7
1
c
6
3
5 .
5
9
3 .
3
5
4
F Exercise 3.8 Estimating and approximating
1 a 110
b 40
2 a i
b i
c i
d i
ii
ii
ii
ii
50
20
16
10
3 a 300.2
c 1000
d 4
c 114
d 17.14
e 1100
f 12 000
49.3
21.6
15.5
9.9
b 1.35
4 8 × $1.15 = $9.20, $9.20 ÷ 8 = $1.15
5 a 14.8 km
b 15.2 km
6 a $153
b 13.5 hours
7 6
2
Cambridge Checkpoint Mathematics 7
Copyright Cambridge University Press 2012
Answers to Practice Book exercises
4 Length, mass and capacity
✦ Exercise 4.1 Knowing metric units
1 a C
b D
c
2 a 900 cm
f 7.5 cm
b 8100 m
g 860 mm
c 5 cm
h 660 cm
3 a 7500 kg
d 9.9 kg
b 0.975 kg
e 0.0002 t
c
f
3t
6000 g
4 a 2l
d 5.5 l
b 6000 ml
e 200 ml
c
f
8800 ml
0.99(0) l
5 a 1000
b cm
c
÷
6 a 27 cm, 280 mm, 0.3 m
c 0.06 kg, 88 g, 0.555 kg
D
d B
d 7 km
i 0.455 km
e 2.2 m
d 55
e 550
f mm, m
b 0.6 l, 635 ml, 7.2 l
d 3.095 km, 3.1 km, 3250 m
7 No. Ali should have used × 1000, not ÷ 1000.
8 4.8 l
9 66 cm or 67 cm
✦ Exercise 4.2 Choosing suitable units
1 a litres
e centimetres
b grams
f kilograms
c tonnes
g millilitres
d centimetres
h metres
2 a X
b Y
c X
d Y
e X
d 12 ml
e 220 g
3 No, this is much too heavy. He has mistaken kg for g.
4 Yes. Lots of types of desk are a bit longer than a metre.
✦ Exercise 4.3 Reading scales
1 a 21.4 m
b 48 cm
c 9.25 mm
f 7.5 l
2 No. Each division is worth 2.5 g not 0.1 g, so the reading is 19.25 g.
3 a 7.7 m
b 21 mg
c 0.3 l
d 125 °C
4 The readings are 195 °C and 165 °C so the difference is 30 Celsius degrees.
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Cambridge Checkpoint Mathematics 7
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Answers to Practice Book exercises
5 Angles
F Exercise 5.1 Labelling and estimating angles
1 a
b EDG or GDE
D
E
G
F
2 a reflex
b obtuse
c acute
d reflex
e obtuse
3 a always
b sometimes
c always
d sometimes
e always
4 a 80°
b 150°
c 230°
d 260°
e 340°
5 a 45°
b 315°
c 270°
d 225°
6 a BAD or ADC
b reflex angle ABC or reflex angle BCD
c reflex angle BAD or reflex angle ADC
F Exercise 5.2 Drawing and measuring angles
1 a 64°
b 217°
c 326°
d 148°
e 74°
f 252°
2 Check angles are of these sizes.
a 46°
b 146°
c 246°
d 346°
e 109°
f 296°
3 332°, 248° and 320°
4 a = 33°, b = 92°, c = 235°
5 a x = 124°, y = 285°, z = 131°
b 124° + 285° + 131° = 540°
6 equilateral triangle
F Exercise 5.3 Calculating angles
1 a 128
b 101
c 83
2 a 114
b 240
c 61
3 a 60°
b 128°
c 30°
d 13°
4 a 97
b 19
c 54
d 41
b 56°
c 81°
5 177°
6 a 135°
7 45°
8 a 105
b 108
9 They add up to 240.
10 a 132°
b 100°
c 32°
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Cambridge Checkpoint Mathematics 7
1
Unit 5 Answers to Practice Book exercises
F Exercise 5.4 Solving angle problems
1 a = 74, b = 42, c = 64
2 a 55° (90 − 35)
b 35° (opposite DGF)
c 55° (opposite BGF)
3 a 104°
b 104°
c 76°
4 The third angle is 180° − (128° + 26°) = 26° so two angles are equal.
5 38° and 104° or 71° and 71°
6 a 65°
b 68°
c 133°
7 a = 115, b = 42, c = 73, d = 65
2
Cambridge Checkpoint Mathematics 7
Copyright Cambridge University Press 2012
Answers to Practice Book exercises
6 Planning and collecting data
✦ Exercise 6.1 Planning to collect data
1 a seconds
b km
c hours
2 a encyclopaedia or internet
c local butcher
d cm
b village officials, local records office or town council
d school register
3 a primary data
b secondary data
4 a S
b S
c secondary data
c E
d primary data
d S
e primary data
e E
5 No (unless her family only includes adults). It would be biased because she has not asked people across a range
of ages.
6 No. If they are waiting they will almost certainly say no.
7 Probably fair, as most people will go to the shops in a week and most people will not play sport every evening. But
possibly biased as younger people might be left at home while adults shop.
✦ Exercise 6.2 Collecting data
1 a 1
2
3
4
You shouldn’t ask for people’s names on a questionnaire; too personal.
Too personal; some people don’t like to give their age.
Leading question; the response boxes don’t allow for anyone to disagree.
3 appears twice; the range 6–10 is not included.
b 2 How old are you?
under 20 years
21–40 years
41–60 years
Over 60 years
3 Do you agree that the local sports centre is a good sports centre?
strongly agree
agree
not sure
disagree
4 How many times did you visit the local sports centre last month?
0 times
1–3 times
4–7 times
strongly disagree
8 times or more
2 a People will disagree on what ‘often’ means.
b Easy to understand; not a leading question; any number can be ticked; no overlaps or missing numbers.
3
0
1 minute to 2 hour 59 minutes
6 hours or more
4
mathematics
technical
2 hours to 5 hour 59 minutes
languages
other
humanities
arts
sports
✦ Exercise 6.3 Using frequency tables
1 a
Favourite pet
Rabbit (R)
Dog (D)
Cat (C)
Horse (H)
Other (O)
5
7
3
1
4
b Dog
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Cambridge Checkpoint Mathematics 7
1
Unit 6 Answers to Practice Book exercises
2
Time
Number of
passengers
3 a
9 am
11 am
1 pm
0
0
4
2
1
2
1
4
2
2
2
2
3
3
1
0
4
3
2
2
Vegetable
Tally
potato (P)
//// //// /
11
//
2
chickpeas (C)
Frequency
beans (B)
//// ///
8
spinach (S)
//// /
6
other (O)
///
3
Total:
30
Tally
Frequency
b Potato
4 a
Fruit
apple (A)
///
3
pineapple (P)
//// ///
8
banana (B)
////
4
melon (M)
///
3
orange (O)
//// /
6
Total:
24
b Pineapple
c 24
5 a
Score
Tally
Frequency
1–10
///
3
11–20
//// ////
10
21–30
//// ////
9
31–40
//// /
6
Total:
28
b 28
c 15. ‘More than half ’ means 21 or more. 9 got 21–30 and 6 got 31–40.
6 a
Score
Tally
Frequency
1–5
//// //// //
12
6–10
//// ////
9
11–15
//// ////
9
16–20
//// ////
10
Total:
40
b Yes; all the groups have about the same frequency.
2
Cambridge Checkpoint Mathematics 7
Copyright Cambridge University Press 2012
Answers to Practice Book exercises
7 Fractions
F Exercise 7.1 Simplifying fractions
1 a
3
b
2
3
c
3
5
d
8, 3
e
22, 2, 2
2 a
1
6
b
1
2
c
1
3
d
5
6
e
4
5
3 a
1
2
b
5
6
c
5
7
d
2
3
e
2
3
21
28
9
12
4
6
8
3
4
15
20
12
16
5 a
18
24
10
16
b The other fractions are all equivalent (will cancel to) 2 , but 10 = 5 .
3
6
16
8
27
63
F Exercise 7.2 Recognising equivalent fractions, decimals and percentages
1
10
19
100
247
1000
b
2
5
16
25
171
500
d
2 a
3
100
b
11
100
c
19
25
d
53
100
e
1
20
3 a
1
4
b
50%
c
4
5
d
70%
e
0.75
4 a
C
b
A
c
C
5 a
1
5
b
80%
c
4
5
70%
b
You are not given the total number of runs.
c
60%
1 a
f
k
g
l
7
10
8
25
51
200
c
h
m
i
n
4
5
9
100
31
500
e
j
o
1
2
3
50
1
125
f 0.2 = 1
5
6 20%
7 a
Copyright Cambridge University Press 2012
Cambridge Checkpoint Mathematics 7
1
Unit 7 Answers to Practice Book exercises
F Exercise 7.3 Comparing fractions
1 a
b
0
3
8
1
1
4
3
8
2 a
b
0
2
5
1
3
10
2
5
3 a 1 part shaded, 1 part shaded, 1
8
c 2 parts shaded, 5 parts shaded, 2
3
3
4
b
6
20
c
3
10
d
4
11
5 a <
b
>
c
<
d
>
4 a
b
2 parts shaded, 3 parts shaded, 3
d
7 parts shaded, 6 parts shaded, 3
10
4
6 She is not correct. Although sevenths are bigger than ninths, 2 = 0.2857...
7
and 4 = 0.4444 … , so 4 is bigger than 2 .
7
9
9
7
11
16
F Exercise 7.4 Improper fractions and mixed numbers
1 a i 21
2
b i 11
4
c i 31
6
d i 28
9
e i 12
3
f i 43
5
2 a 11
e
2
42
3
3 a
17
2
e
16
5
ii 5
2
ii 5
4
ii 19
6
ii 26
9
ii 5
3
ii 23
5
b 51
c 31
2
f 22
7
4
g 53
5
b 19
c 9
4
g 29
5
3
20
f 9
d 31
3
h 55
6
d 29
7
35
h 3
4 No. He should have started with 7 × 9 (the denominator is 9, not 7),
then added the 7 to get 70 .
9
2
5 a
37
b 43
6 a
32
b 11
12
3
12
3
Cambridge Checkpoint Mathematics 7
Copyright Cambridge University Press 2012
Answers to Practice Book exercises Unit 7
F Exercise 7.5 Adding and subtracting fractions
1 a
2
3
b
2
5
c
2
7
d
4
5
e
6
11
f
1
5
g
4
9
h
4
7
i
4
15
2 a
1
2
b
1
2
c
2
5
d
1
e
1
3
f
1
2
g
1
3
h
4
5
i
1
5
3 a
11
b
12
c
11
d
12
e
1 12
f
12
4 a
1
2
b
1
2
c
5
8
d
7
9
e
1
2
f
1
3
g
1
6
h
3
11
i
1
2
5 a
11
b
11
c
11
d
11
e
12
f
3
110
3
4
5
4
6
8
5
4
9
9
6 For example, 3 + 7
4
8
F Exercise 7.6 Finding fractions of a quantity
1 a $6
b 5 cm
c 3 kg
d 4 mm
e 2
f 6
2 a 4 mm
b 30 km
c $10
d 8 kg
e 9
f 8
3 a $55
b 252 km
c 23 m
d 96 l
e 115
f 84
4 a 43
b 2
c 86
d
2 14
e
2 16
f
2 92
g
52
d
41
5
e
21
f
12
g
10 1
e
4
54 1
2
f
65 3
4
e
34 1
f
36 1
3
5 30 × 3 (= 18); the other two both equal 20.
5
6 38 582
7 143 km
F Exercise 7.7 Finding remainders
b
4 13
b
41
3
3 a
128 1
2
4 a
5 a
c
22
c
21
4
b
80 3
4
c
171 1
3
d
36 1
2
36 2
b
65 3
c
48 1
d
54 43
7
b 24
1 a
41
2 a
21
2
2
15
13
5
2
9
3
5
2
3
6 6
7 9
8 5
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Cambridge Checkpoint Mathematics 7
3
Answers to Practice Book exercises
8 Symmetry
F Exercise 8.1 Recognising and describing 2D shapes and solids
1 a isosceles triangle
2
3
b parallelogram
Name of solid
Number of faces
Number of edges
Number of vertices
square-based pyramid
5
8
5
triangular-based pyramid
4
6
4
triangular prism
5
9
6
cuboid
6
12
8
4 triangular-based pyramid
5 a triangle and a trapezium
6 cuboid and square-based pyramid
F Exercise 8.2 Recognising line symmetry
1
One line of symmetry
Two lines of symmetry
B, C, F, G
A, D, E
Shape
2 A: 1, B: 2, C: 0, D: 2, E: 0, F: infinitely many, G: 1, H: 0, I: 1, J: 2, K: 0, L: 4, M: 1
3 a
b
c
4 a, b
i
c i vertical
ii
iii
ii diagonal
iv
iii
diagonal
iv
horizontal
5
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Cambridge Checkpoint Mathematics 7
1
Unit 8 Answers to Practice Book exercises
F Exercise 8.3 Recognising rotational symmetry
1 A: 2, B: 1, C: 2, D: 5, E: 1, F: 6, G: 2, H: 4, I: 1, J: infinity, K: 2, L: 2, M: 1, N: 3
2
Number of lines of symmetry
0
1
2
3
4
1
Order of rotational
symmetry
2
F
3
4
D, E
C
B
A
3 For example:
4 a Any three from:
2
Cambridge Checkpoint Mathematics 7
b
Copyright Cambridge University Press 2012
Answers to Practice Book exercises Unit 8
F Exercise 8.4 Symmetry properties of triangles, special quadrilaterals and polygons
1
Sides
all different
1 equal pair
2 equal pairs
1 equal pair
J
B
2 equal pairs
F
E
I
C
A, H
all different
Angles
all equal
D, G
all equal
2
Rotational symmetry
Number of lines of
symmetry
order 1
order 2
0
D, G
E
1
B, F, J
2
order 3
order 4
C, I
3
H
4
A
3 Two sides same length, one line of symmetry, order 1 rotational symmetry
4 Angles: square all 90°, rhombus two pairs equal angles but none 90°
Symmetry: square has four lines and order 4, rhombus has two lines and order 2
5 a (4, 4)
b (6, 4)
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c (7, 3) or (8, 2)
d (3, 3)
e (2, 4)
Cambridge Checkpoint Mathematics 7
3
Answers to Practice Book exercises
9 Expressions and equations
✦ Exercise 9.1 Collecting like terms
a 3x
b
2z
c 2x + y
d 2z + x
e
2 a 4a
g 6g
b
h
7b
h
c 11c
i 8i
d 9d
j 6j
e 13e
k 4k
1
3
a
b
18x 18x
8x 8x
x
x
7x 7x
2x + 2y + z
f
l
15f
y
4x 4x
3x 3x
8x 8x
5x 5x
3x 3x
4 a 7x + 5y
g 30 + 11w
b
h
10z + 6a
4x + 6y
c 7a + 9b
i 4a + b
5 a 6ab + 8xy
d 5ej + 3hy
b
e
6rd + 11th
3v + 16rv
c 11tv + 4jk
f 3nu
6
f
15x 15x
10x 10x
7x 7x
3x + 2y
d 7x + 7
j 2w + 20y
e 2d + 2
f
k 200a + 5g + 30
2f + 9g
a Maddi added terms that are not like terms.
b Maddi thought 4t − t = 4, but it is 3t. Maddi thought that 5rg and 2gr were not like
terms, but they are.
7
17a + 11b
8a + 6b
3a + 4b
3b
9a + 5b
5a + 2b
3a + b
4a + 3b
2a + b
2a + 2b
✦ Exercise 9.2 Expanding brackets
1
a 3a + 6
g 8 + 4f
b 5b + 15
h 56 + 8z
c
i
3c + 6
27 + 9y
d 5d − 5
j 16 − 4x
e 4e − 36
k 7 − 7w
f
l
3f − 24
14 − 7v
2 a 10p + 5
g 6 + 12v
b 21q + 14
h 48 + 32w
c
i
18r + 27
60 + 70x
d 33s − 44
j 15 − 25x
e 4t − 10
k 20 − 15x
f
l
20u − 4
25 − 40x
3 a He forgot to multiply the second part of the expression in the brackets.
b He added, rather than multipled, the second part of expression in the brackets.
c He collected terms that were not like terms.
4 2(10x + 8); all the others multiply to give 18x + 24.
✦ Exercise 9.3 Constructing and solving equations
a x=4
g x = 27
m x = 16
b x=3
h x=4
c x=7
i x = 10
d x=6
j x=7
e x = 15
k x = 50
f x = 10
l x = 27
2 a x = 11
g x = 18
b x=4
h x = 64
c x = 18
d x = 25
e
x=7
f x=5
3 a x=3
g y = 44
b x=2
h y = 10
c x=5
i z=3
d x = 13
j z=7
e y=4
k z = 12
f y=9
l y = 80
1
4 a n + 5 = 21, n = 16
d n = 20, n = 100
b n − 5 = 21, n = 26
e 5n + 5 = 20, n = 3
5 a 3x + 10 = 28, x = 6
b 2y + 20 = 25, y = 2.5
5
Copyright Cambridge University Press 2012
c 5n = 20, n = 4
f n − 5 = 4, n = 45
5
Cambridge Checkpoint Mathematics 7
1
Answers to Practice Book exercises
10 Averages
✦ Exercise 10.1 Average and range
1 a 20 s
b 18 s
c 24 s
2 a black
b Not possible; only numbers have a median.
c Not possible; only numbers have a range.
3 a i
b i
44
88%
ii
ii
iii
iii
40
80%
14
28%
4 a i The nurse did not put the masses in order.
b 3.2 kg
ii
0.9 kg
5 Either 1.84 m or 1.49 m
6 a 38
b 5–10 km
c False
7 a 6
b 18
c 9
d 8
8 Two are 12 km. The third is either 17 km or 9 km.
✦ Exercise 10.2 The mean
1 a
177 g
b The median
2 a
0 mm in both weeks
c 185 g
b
c
2 mm and 1 mm
1.5 mm
3 24
4 a $30
b 5 jobs
5 a 7 matches
b 49.5
c No. The median (49) and the mean are both less than 50.
6 a 32
b 2
7 30 years
✦ Exercise 10.3 Comparing distributions
1 a A: 7 years; B: 4 years
b A: 8 years; B: 5 years
2 a Sami: 2.25; Marta: 2.5
b Marta
3 a Test 1: 29; Test 2: 35
b Test 1
c A
d A
c Test 2
4 a Raj: 31 minutes; Tamasa: 27 minutes
b Raj: 17 minutes; Tamasa: 9 minutes
c Raj’s were longer on average by 4 minutes; Raj’s times varied more than Tamasa’s.
5 a City (3.25) was higher than United (2.7)
b City (1.5) was higher than United (1.4)
6 a The averages were about the same (the median or the mean).
b Jaouad had a smaller range (5) compared to Tsegaye (10) and was more consistent.
7 a true
b false
c cannot tell
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d true
e cannot tell
Cambridge Checkpoint Mathematics 7
1
Answers to Practice Book exercises
11 Percentages
✦ Exercise 11.1 Simple percentages
1 Check students’ drawings.
2 a
about 70%
3 a
90%
b about 3
10
b 45%
c 36%
d 18%
4 They are 40%, 32%, 33 1 %, 35% so the order is 8 , 1 , 7 and 2 .
25 3 20
3
5 37 1 %
5
2
6 a
Tara 2 , Mina 11
5
b Tara 40%, Mina 55%
20
7 60% + 25% + 15% = 100%
8 a
b 6%
42%
c 52%
9 75%
10 5%
✦ Exercise 11.2 Calculating percentages
1 a
2
3 a
b 8 kg
$20
c 80 m
d 14 people
e 34 years
10%
30%
50%
70%
100%
25
75
125
175
250
b 13.5
36
c 25 people
d 540 g
4 26
5 $57
6 No. 20% of $35 dollars is $7.
7 30
8 a
60
b 108
c 48
✦ Exercise 11.3 Comparing quantities
1
a
b
A: 70%, B: 60%
2 a
Test 2 (90%)
b
3 a
Thursday 80%, Saturday 82%
Class B
c Class A
Test 3 (84%)
b Saturday
4 This year they scored in 70%. That is better.
5 It might not be true if fewer people voted.
6 Badam has a greater percentage. Arcot has 28% aged under 18, and Badam has 30%.
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Cambridge Checkpoint Mathematics 7
1
Answers to Practice Book exercises
12 Constructions
✦ Exercise 12.1 Measuring and drawing lines
1 a 8.0 cm, 80 mm
d 10.2 cm, 102 mm
b
e
1.5 cm, 15 mm
4.4 cm, 44 mm
c 6.8 cm, 68 mm
f 12.0 cm, 120 mm
2 Check students’ lines are drawn accurately within ± 2 mm.
✦ Exercise 12.2 Drawing perpendicular and parallel lines
1 a Check students’ parallel lines are drawn accurately within ± 2 mm and correctly spaced.
b Check students’ parallel lines are drawn accurately within ± 2 mm and correctly spaced.
2 Check students’ lines are drawn accurately within ± 2 mm. Check position of C and that the line from C is
perpendicular to AB.
3 Check students’ lines are drawn accurately within ± 2 mm. Check position of Y and Z and that the lines from Y
and Z are perpendicular to WX.
✦ Exercise 12.3 Constructing triangles
1 Check students’ triangles are drawn accurately with lengths within ± 2 mm, angles within ± 2°.
2 Check students’ triangles are drawn accurately with lengths within ± 2 mm, angles within ± 2°.
3 a Check students’ triangles are drawn accurately with lengths within ± 2 mm, angles
within ± 2°.
b AC = 8 cm ± 2 mm
c Angle BCA = 48° ± 2°
4 a Check students’ triangles are drawn accurately with lengths within ± 2 mm, angles
within ± 2°.
b AB = 7 cm ± 2 mm
c AC = 5.8 cm ± 2 mm
d Angle BAC = 77° ± 2°
e Sum should be 180°.
f Check students’ reasons; expect a logical answer to justify the decision on the accuracy of the triangle.
5 Check students’ triangles are drawn accurately with lengths within ± 2 mm, angles within ± 2°.
6 No. Ahmad: AC ≈ 6.8 cm, Shen: AC ≈ 6.7 cm; students should give a logical answer to justify the assertion.
✦ Exercise 12.4 Constructing squares, rectangles and polygons
1 Check students’ squares are drawn accurately with lengths within ± 2 mm, angles within ± 2°.
2 Check students’ rectangles are drawn accurately with lengths within ± 2 mm, angles
within ± 2°.
3 Check students’ hexagons are drawn accurately with lengths within ± 2 mm, angles
within ± 2°.
4 Check students’ pentagons are drawn accurately with lengths within ± 2 mm, angles
within ± 2°.
5 Check students’ diagrams are drawn accurately with lengths within ± 2 mm, angles
within ± 2°.
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Cambridge Checkpoint Mathematics 7
1
Answers to Practice Book exercises
13 Graphs
F Exercise 13.1 Plotting coordinates
1 D(−3, 4), E(0, 3), F(4, −1), G(−2, −3)
2 a
3 a
b
P(−4, −2), Q(6, −2)
(1, −2)
b (0, 1)
y
4
S
3
2
1
0
–4 –3 –2 –1
–1
–2
1
2
3
x
R
–3
–4
4 a
4
b D(−2, 4)
y
4
D
3
A
2
1
C
0
–5 –4 –3 –2 –1
–1
–2
B
–3
E
–4
5 a
b
(−3, −2)
6 a
A
1
2
3
4
5
x
(−1, 0)
y
7
b CA and CB are both 5 units long.
6
5
4
3
2
C
1
0
–4 –3 –2 –1
–1
7 a
(3, −2)
B
1
2
3
x
b (−1, 1)
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c (0, 3)
d (2, 1)
Cambridge Checkpoint Mathematics 7
1
Unit 13 Answers to Practice Book exercises
8 a
b (2, 3)
y
4
B
3
2
1
–6 –5 –4 –3
–2 –1 0
–1
M
–2
1
2
3
x
–3
–4
–5
–6
A
F Exercise 13.2 Lines parallel to the axes
1 a y=2
b x = −3
2 a F, M and L
b
c y = −4
F, G and H
3 a x = 4 and y = 7
4 a
d x=2
b x = −3 and y = −6
c x = 0 and y = 9
b (−4, 2) and (−4, −5)
y
3
2
1
–5 –4 –3 –2 –1 0
–1
–2
1
2
3
x
–3
–4
–5
–6
5 a y = −5
6 a
b x=3
c y=0
y
6
5
4
3
2
1
–6 –5 –4 –3 –2 –1–1
0
1
2
x
–2
b (−2, 3), (−2, 5), (−6, 3) and (−6, 5)
c x = −4 and y = 4
7 y = −6
2
Cambridge Checkpoint Mathematics 7
Copyright Cambridge University Press 2012
Answers to Practice Book exercises Unit 13
F Exercise 13.3 Other straight lines
1 a
The missing values are 0, 2, 3 and 6.
b
y
6
5
4
3
2
1
–4 –3 –2 –1 0
–1
–2
2 a
The missing values are −2, 0, 6 and 8.
b
1
2
3
4
1
2
3
4
x
y
8
7
6
5
4
3
2
1
0
–2 –1–1
1
2
x
–2
–3
–4
3 a
The missing values are −2, 0, 6 and 8.
b
y
10
9
8
7
6
5
4
3
2
1
–4 –3 –2 –1
–1
–2
0
x
–3
–4
c (−2, 0)
d (0, 4)
4 a The missing values are 9, 7, 4 and 1.
c (6, 0)
b
y
8
7
6
5
4
3
2
1
0
–3 –2 –1
–1
Copyright Cambridge University Press 2012
1
2
3
4
5
6
7
x
Cambridge Checkpoint Mathematics 7
3
Unit 13 Answers to Practice Book exercises
5 a
b
The missing values are 11, 1 and −3.
y
12
11
10
9
8
7
6
5
4
3
2
1
–2 –1 0
–1
–2
1
2
3
4
1
2
3
4
x
–3
–4
6 a
The missing values are −1, 1, 3, 7 and 11.
b
y
12
11
10
9
8
7
6
5
4
3
2
1
0
–2 –1
–1
–2
x
7 A is y = 2 − x; B is y = 2 + x; C is y = 2x
8 a, b
y
6
5
4
3
c
(−2, 2)
2
1
–5 –4 –3 –2 –1 0
–1
4
1
2
x
Cambridge Checkpoint Mathematics 7
Copyright Cambridge University Press 2012
Answers to Practice Book exercises
14 Ratio and proportion
✦ Exercise 14.1 Simplifying ratios
1 a 1:6
b
6:1
c
3:4
d
5:2
2 a 1:2
b
1:3
c
3:2
d
1:1
3 a 4:3
b
3:2
4 a 1:2
g 6:1
b 1 : 10
h 6:1
c 1:3
i 20 : 1
d 1:7
j 3:1
e 1:4
k 5:1
f 1:5
l 8:1
5 a 2:9
g 5:4
b 2 : 15
h 8:3
c 8:9
i 11 : 2
d 2:5
j 8:5
e 4:9
k 8:5
f 4 : 15
l 7:2
6 No. 250 : 100 simplifies to 5 : 2.
✦ Exercise 14.2 Sharing in a ratio
1 Total number of parts: 1 + 3 = 4
Value of one part: $40 ÷ 4 = $10
Ain gets: 1 × $10 = $10
Geb gets: 3 × $10 = $30
2 a $6, $18
b
$9, $36
c
$7, $42
d
$24, $8
e
$30, $6
f
$28, $4
3 a $22, $33
b
$21, $28
c
$24, $40
d
$20, $8
e
$28, $20
f
$22, $6
4 20
5 600 litres
6 a 1:2
b $28 000
7 C : P = 120 : 16 = 15 : 2; 34 000 ÷ 17 = 2000; 2 × 2000 = 4000 pike
8 Age. Age: Estela gets 15. Dolls: Estela gets 14.
✦ Exercise 14.3 Using direct proportion
1 a
$2.40
b
$12
2 a
8 hours
b
14 hours
3 a
9
b
156
4 1 chorizo weighs: 500 ÷ 4 = 125 g
7 chorizos weigh: 7 × 125 g = 875 g
5 a
180 g
b
1260 g or 1.26 kg
6 a
$28
b
$84
7 a
€83
b
€415
8 He worked it out for 6 people, not 10. The recipe needs 700 g of potato for 10 people.
9 $375
Copyright Cambridge University Press 2012
Cambridge Checkpoint Mathematics 7
1
Answers to Practice Book exercises
15 Time
✦ Exercise 15.1 The 12-hour and 24-hour clock
1 a
1 20 am
b 3 45 pm
c 8 20 pm
d 12 35 pm
2 a
00 05
b 12 34
c 22 50
d 09 20
3 a
1 hour 10 minutes
b 3 hours 24 minutes
c 2 hours 44 minutes
4 a
2 hours 7 minutes
b 4 hours 10 minutes
c 3 hours 18 minutes
5 a
4 hours 42 minutes
b 3 hours 27 minutes
6 12 40 pm
7 a
1 hour 47 minutes
b 21 34
8 a
86 minutes or 1 hour 26 minutes
9 a
13 15
10 a
18 15 on 6 December
c 14 44
b 10 08
b 01 15 the next day
b 07 15 on 7 December
✦ Exercise 15.2 Timetables
1 a
2
b
12 20 pm
Airport
13 15
Hotel
13 35
Zoo
13 47
Town centre
14 04
i 20 minutes
3 a
c
32 minutes
b 1 hour 14 minutes
2 hours 30 minutes (2 1 hours)
d 13 10
4 a
15
b 52
5 a
46 minutes
b 2 hours 26 minutes
6 a
15 45
ii
2 hours 30 minutes
c
25
iii
4 hours 20 minutes
2
b
d 08 35
c
15 28
d 2 hours 28 minutes
11 30
✦ Exercise 15.3 Real-life graphs
1 a
20 km
b 1 hour
2 a
10 minutes
b The graph becomes horizontal.
3 a
3 km
b 17 30
c 4 km
4 a
50 cm
b 2 hours
c
Copyright Cambridge University Press 2012
c 1.5 hours
c 20 minutes
d 6 km
d 8 km
3 hours
Cambridge Checkpoint Mathematics 7
1
Unit 15 Answers to Practice Book exercises
5 a
y
8
b
Distance (km)
3 km
6
4
2
0
x
0
1
2
Time (hours)
3
c Faster in the first hour. The graph is steeper.
6 a
c
b
Distance from start (km)
100 km
400 km
y
200
100
0
7
x
0
1
2
4
3
Time (hours)
5
6
y
9
Distance (km)
8
7
6
5
4
3
2
1
0
2
x
0
1
2
3
Time (hours)
4
Cambridge Checkpoint Mathematics 7
Copyright Cambridge University Press 2012
Answers to Practice Book exercises
16 Probability
F Exercise 16.1 The probability scale
1 a unlikely or very unlikely
d even chance
2
C
A
c
impossible
B D
0
1
3
E
F
G
0
4
b very likely
e even chance
1
sunshine rain
0
cloud
1
5 Double 0.6 is 1.2; a probability cannot be more than 1.
F Exercise 16.2 Equally likely outcomes
1
11
1
100
b
3 a 0.05
1 a
2 a
4 a
4 or 16%
25
2
11
9
100
c
b
0.2
b
14 or 56%
25
b
4
11
1
5
d
0
e
8
11
c
0.2
d
0.75
e
0
c
4 or 80%
5
c
27
35
8 = 2 or 8%
100
25
c
5 The outcomes may not be equally likely.
6 a
7 a
8 a
13 or 52%
25
12
35
21 or 42%
50
b
b
b
18 or 72%
25
20 = 4
35
7
42 = 2
63
3
Copyright Cambridge University Press 2012
c
Cambridge Checkpoint Mathematics 7
1
Unit 16 Answers to Practice Book exercises
F Exercise 16.3 Mutually exclusive outcomes
1 a E: 1 ; T: 1 ; F: 1
2
b i
no
3
6
ii
iii
yes
yes
2 a No, both have an A.
b Yes. They have different letters.
c No, both have a U and a T.
3 a T (true)
b
X (cannot tell)
c
T (true)
4 a Yes
b
Yes
c
No; 12 is in both.
d
Yes
5 a A: 11 , B: 9 , C: 9
b i
100
100
no
ii
100
yes
iii
yes
F Exercise 16.4 Estimating probabilities
b
1
5
c
9
10
2 a 58%
b
8%
c
34%
3 a 57%
b
0.4%
c
8%
4 a 47%
b
88%
c
27%
5 a i 1
ii 3
1 a
7
10
20
4
d
43%
iii 3
4
b Seasonal variations in the weather affect the probabilities in different times of the year.
6 a 1 is 18%; 2 or 3 is 31%; 4,5 or 6 is 51%
()
()
()
b 17% 16 , 33% 13 and 50% 1
2
c Yes. The experimental and theoretical probabilities are similar.
7 a
2
8 , about 23%
35
b
18 , about 29%
62
Cambridge Checkpoint Mathematics 7
Copyright Cambridge University Press 2012
Answers to Practice Book exercises
17 Position and movement
F Exercise 17.1 Reflecting shapes
1 a, c and d
2 a
b
c
d
3 a
b
c
d
4y ay y
by y y
7
7 7
7
7 7
7
7 7
6
6 6
6
6 6
6
6 6
5
5 5
5
5 5
5
5 5
4
3
4 4
3 3
4
3
4 4
3 3
4
3
4 4
3 3
2
2 2
2
2 2
2
2 2
1
1 1
1
1 1
1
1 1
0
0 0
x x x
0 01 021 132 243 354 465 576 67 7
0
0 0
x x x
0 01 021 132 243 354 465 576 67 7
0
0 0
x x x
0 01 021 132 243 354 465 576 67 7
5 a
b
6 a x=4
c y y y
c
b y=5
c y=4
d
d x=6
e y=2
f x=7
F Exercise 17.2 Rotating shapes
1 a
b
c
CCCC
d
CCCC
CCCC
CCCC
2 a
b
c
CCCC
d
CCCC
CCCC
Copyright Cambridge University Press 2012
CCCC
Cambridge Checkpoint Mathematics 7
1
Unit 17 Answers to Practice Book exercises
3 ay yy y
b y yy y
c y yy y
666 6
666 6
666 6
y yy y
666 6
444 4
444 4
444 4
444 4
222 2
222 2
222 2
222 2
000 0
xxx x
000 0111 1222 2333 3444 4555 5666 6
000 0
xxx x
000 0111 1222 2333 3444 4555 5666 6
000 0
xxx x
000 0111 1222 2333 3444 4555 5666 6
000 0
xxx x
000 0111 1222 2333 3444 4555 5666 6
4 a Rotation 90° clockwise, centre (3, 5)
c Rotation 90° clockwise, centre (4, 3)
e Rotation 180°, centre (5, 6)
5 a
d
b Rotation 180°, centre (3, 5)
d Rotation 180°, centre (3.5, 3)
f Rotation 180°, centre (4, 1.5)
b 4
F Exercise 17.3 Translating shapes
1 a
b
c
d
2 a 2 squares right, 3 squares down
b 2 squares left, 1 square down
3 a, b
c 5 squares right, 3 squares up
c 4 squares up
C
B
A
d Add the 3 squares right and the 2 squares right; this gives 5 squares right. Add the 2 squares up and the
1 square up; this gives 3 squares up.
4 Yes. 4 squares left and then 1 square left totals 5 squares left. 3 squares up and then 5 squares down is the same
as 2 squares down.
5 a
y
6
5
4
3
2
1
b 4 squares left and 3 squares up
C
A
R
B
P
0
0 1 2 3 4 5 6
Q
x
cThey are exactly opposite.
6 a
2 squares left, 5 squares up
b 2 squares right, 5 squares down
7 Dakarai has not said whether the movement across should be to the left or to the right.
2
Cambridge Checkpoint Mathematics 7
Copyright Cambridge University Press 2012
Answers to Practice Book exercises
18 Area, perimeter and volume
F Exercise 18.1 Converting between units for area
1 a mm2
b
2 a 5
g 35 000
b 5.1
h 1
c
cm2
km2
d
m2
c 25.1
i 4.55
d
400
e
680
f
80 000
3 Yuuma has divided by 100 and not by 1 000 000.
F Exercise 18.2 Calculating the area and perimeter of rectangles
1 a 48 m2
b
21 cm2
c
220 mm2
2 a 34 mm
b
11 m
c
100 cm
3 70 060 mm2 or 700.6 cm2
4 a 3m
b
16 m
5 a 210 mm2
b
2.1 cm2
6
Rectangle
Length
Width
Area
Perimeter
A
3 cm
15 cm
45 cm
B
7 cm
3m
21 m
20 m
C
8 mm
5 mm
40 mm2
26 mm
D
5 mm
7 mm
35 mm2
24 mm
E
5m
2.5 m
12.5 m
15 m
2
2
2
36 cm
7 2.1 m2
8 Mia. 1 × 18, 2 × 9, 3 × 6. 1 × 18 is the same as 18 × 1.
F Exercise 18.3 Calculating the area and perimeter of compound shapes
1
a A = 36 m2, P = 28 m
c A = 19 m2, P = 18 m
2 a A = 16 m2
b A = 29 m2, P = 28 m
d A = 186 m2, P = 70 m
b A = 89 m2
3 Area A: has multiplied two different heights; should be 10 × 18 = 180 mm2
Area B: height is 6 mm not 8 mm; should be 12 × 6 = 72 mm2
Area C: correct
Total area = 332 mm2
Perimeter: has missed out left side of rectangle B and part of top of rectangle C; should be 132 mm
Copyright Cambridge University Press 2012
Cambridge Checkpoint Mathematics 7
1
Unit 18 Answers to Practice Book exercises
F Exercise 18.4 Calculating the volume of cuboids
1 a 120 mm3
b
240 cm3
2 a 60 000 cm3 or 0.06 m3
c
18 000 cm3
b
8000 mm3 or 8 cm3
3 He thought the cm were m. Volume = 0.002 m3 or 2000 cm3
4 a 12 500
5 a 8.816 m
3
b
16
c
b
2 × 0.8 × 6 = 9.6 m
1.2
d 99 000
3
6 150 kg
F Exercise 18.5 Calculating the surface area of cubes and cuboids
1 a 76 m2
b 310 mm2
c
88 cm2
2 B; surface area of A = 600 mm2, surface area of B = 700 mm2
3 B; surface area of A = 24 cm2, surface area of B = 22 cm2
2
4 a 113.72 cm2
b
2 × 8 × 3 + 2 × 8 × 3 + 2 × 3 × 3 = 114 cm2
5 a 60 000 cm2
b
6 m2
6 a 13 tins
b
$51.87
Cambridge Checkpoint Mathematics 7
Copyright Cambridge University Press 2012
Answers to Practice Book exercises
19 Interpreting and discussing results
Interpreting and drawing pictograms, bar charts,
F Exercise 19.1 bar-line
graphs and frequency diagrams
1 a 20
2 a
b 15
c 25
d 170
Monday
Tuesday
Wednesday
Thursday
Friday
b
Number of texts Maria received in one week
Number of texts
12
10
8
6
4
2
0
Monday
Tuesday
Wednesday
Thursday
Friday
Day of week
3 a 9
b 12
4
c 43
Diameters of small ammonites in collection
16
14
Frequency
12
10
8
6
4
2
0
1 – 20
21 – 40
41 – 60
61 – 80
Diameter (mm)
5 16 ÷ 4 = 4; 20 + 10 + 16 + 6 = 52 pens
F Exercise 19.2 Interpreting and drawing pie charts
1 a rugby
b football
c basketball and hockey
d half of 100 = 50
2 a football
b netball
c rounders and hockey
d Not told how many girls there are in total
Copyright Cambridge University Press 2012
Cambridge Checkpoint Mathematics 7
1
Unit 19 Answers to Practice Book exercises
3 a Total number of TVs = 18 + 12 + 2 + 8 = 40 TVs
Number of degrees per TV = 360 ÷ 40 = 9°
Number of degrees for each sector:
Panasonic = 18 × 9° = 162°
Samsung = 12 × 9° = 108°
Logik = 2 × 9° = 18°
Phillips = 8 × 9° = 72°
b
Phillips
72°
Logik
18°
Panasonic
162°
Samsung
108°
4
Other
32°
Crisps
140°
Chocolate
108°
Nuts
80°
5 a
Favourite day
Frequency
Number of degrees (°)
Friday
15
90
Saturday
32
192
Sunday
9
54
Other
4
24
b
Others
24°
Sunday
54°
Friday
90°
Saturday
192°
F Exercise 19.3 Drawing conclusions
1 a i 29
ii 44
b In Jazmin’s street, most people walk and none take a train. In Sarah’s street, most people go by car, the second
most common is train and walking is the least common.
c Yes, most people walk to work.
d No, most people go either by car or train.
2 a
b
c
d
g
i 55
ii 43
Accept any sensible reason.
Two comments comparing boys’ and girls’ favourite canteen food
rice
e humous
f potato
i potato ii rice
3 a 30 marks might be 100%.
b Two appropriate comments comparing the geography test and the history test scores
c i 31–40 ii 21–30
4 aNo. He spends more time than Oditi, but not twice as much, as the angle of the sector is not that much bigger.
b Yes, the angles are the same so they spend the same amount of time on sport.
2
Cambridge Checkpoint Mathematics 7
Copyright Cambridge University Press 2012