Math Review 1 - Lead.com.sg

  Class:
Name:
  Date:
5
3
Review 1
1
6
Section A
Read the questions carefully. Each question has 4 options (1, 2, 3 or 4).
Choose one option and write its number in the brackets provided.
(1) In 24 795, which digit is in the ten thousands place?
(1) 5
(2) 2
(3) 7
(4) 9
( 2 )
1
5
(2) Express 1— h in minutes.
(1) 61
(3) 72
(3) 4.324 5 4 оЂ± 0.3 оЂ±
(2) 65
(4) 120
( 3 )
. What is the number in the box?
 
(1) 0.024
(3) 0.324
(2) 0.24
(4) 24
)
( 3
)
.
(4) 36% as a fraction in the simplest form is
36
100
(2) —
9
25
(4) —
16
25
(1) —–
(3) —
(5)
Peter and Jane share $474. Peter receives twice as much money as Jane.
How much does Peter receive?
(1) $118.50
(2) $158
(3) $237
(4) $316
Review 1
( 1
9
20
( 4 )
57
(6) Siti earns $950 a month. How much does she earn in a year?
(1) $9500
(2) $11 400
(3) $12 350
(4) $13 300
( 2 )
(7) Which of the following is the net of this cuboid?
(1)
(2)
(3)
(4)
( 4 )
(8) The figure shows a square with a side of 38 cm. What is the area of the unshaded
part?
(1) 152 cm2
(2) 361 cm2
(3) 1083 cm2
(4) 1444 cm2
( 3 )
(9)
The figure below is not drawn to scale. AB and CD are straight lines.
Find оЂЇx.
(1) 45В°
D
(2) 73В°
A
135В°
(3) 118В°
(4) 135В° x
62В°
( 2 )
B
C
58
Review 1
(10)The graph below shows the number of fruits a shopkeeper sold in 5 weeks.
300
Number 200
of
fruits sold 100
0
1
2
3
Week
4
5
If the shopkeeper sold the fruits at $0.30 each, how much did he earn for the five
weeks?
(1) $300
(2) $900
(3) $1000
(4) $3000
( 1 )
(11)The figure below is not drawn to scale. ABC is an isosceles triangle. ACE and
BCD are straight lines. Find оЂЇm.
D
A
m
C
50В°
E
B
(1) 50В°
(3) 80В°
(2) 60В°
(4) 100В°
( 3 )
(12)A pen costs twice as much as a ruler. Ali spends $6 on 3 pens and 2 rulers.
How much does a pen cost?
(1) $0.75
(2) $1.50
(3) $2.25
(4) $4.50
( 2 )
(13)The average of two numbers is 81. The difference between the numbers is 26.
What is the smaller number?
(1) 68
(2) 94
(3) 136
(4) 162
( 1 )
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59
(14) Anu and Jane had some stickers in the ratio 1 : 5. If Jane had 92 stickers more
than Anu, how many stickers did they have altogether?
(1) 23
(2) 46
(3) 115
(4) 138
( 4 )
(15)There are 2 books in a box. The mass of each book is r g. The box is 200 g lighter
than each book. What is the total mass of the box and the two books?
(1) 2r g
(2) (2r – 200) g
( 4 )
(3) 3r g
(4) (3r – 200) g
Section B
Read the questions carefully. Write your answers in the spaces provided.
(16)Find the value of 129 оЂІ 85 оЂґ 2 оЂ± 12.
129 – 85 ÷ 2 + 12= 129 – 42.5 + 12
= 86.5 + 12
= 98.5
98.5
(17)What is the sum of all the factors of 12?
12= 1 Г— 12
=2Г—6
=3Г—4
1 + 2 + 3 + 4 + 6 + 12 = 28
28
3 in order, beginning with the smallest.
3  ,  —
5  ,  —
(18)Arrange —
8
5
4
5
24 3
25 3
30
— = —– , — = —– , — = —–
8
40 4
40 5
40
3 5 3
— — —
5, 8, 4
60
Review 1
(19)5.79 оЂі
= 5790. What is the missing number in the box?
1000
(20)What is the mass of the bag of rambutans?
5
4
0
kg
3
1
2
5
4
0
kg
3
1
2
5
kg 300  g
(21)How many faces are there in the solid below?
4
(22)Simplify 3a оЂ± 5 оЂІ 2a оЂ± 6.
a + 11
(23)Mr Tan’s salary is $3000 a month. He used 42% of it to pay bills and spent 16% of
it on transport. How much did he have left?
100% – 42% – 16% = 42%
42
—– × $3000 = $1260
100
$
Review 1
1260
61
Study the graph to answer question 24.
The graph below shows the number of visitors to the Science Centre in a particular
week. The Science Centre is closed on Monday.
700
600
Number
of
visitors
500
400
300
200
100
0
Sun
Mon
Tue Wed Thu
Days of the week
Fri
Sat
(24)What fraction of all the visitors came on Thursday? Give your answer in the
simplest form.
650 + 500 + 550 + 400 + 500 + 600 = 3200
1
—
8
1
400
4
—–— = —– = —
8
3200
32
(25)The figure below is not drawn to scale. MNOP is a rhombus and MOQ is a
straight line. Find оЂЇPOQ.
M
Since MP = PO, MPO is an isosceles triangle.
P
POM = (180° – 80°) ÷ 2
= 100В° Г· 2
= 50В°
80В°
N
POQ = 180° – 50°
= 130В°
O
Q
130
В°
(26)A garment factory produces 4500 shirts a day. If the factory produces shirts
continuously for 5 days every week, how many shirts are produced in 3 weeks?
4500 Г— 5 = 22 500
22 500 Г— 3 = 67 500
67 500 shirts
62
Review 1
(27)Find the area of a triangle with base 24 cm and height 10 cm.
1
— × 24 × 10 = 120 cm2
2
120
cm2
(28)(a) Draw a line passing through Point P that is parallel to line CD.
(b) Draw a line from Point P that is perpendicular to line CD.
C
P
D
(29)In the figure below, what is the smallest number of squares that must be added so
that line AB becomes a line of symmetry?
B
2
A
(30)The perimeter of a rectangle is 40 cm. The ratio of its length to its breadth is
3 : 2. Find the length of the rectangle.
Total units= 3 + 2 + 3 + 2 = 10
1
10 units→ 40 cm
1 unit→ 4 cm
3 units→ 12 cm
12
Review 1
cm
63
7
2
of my sister’s beads are yellow. —
of the remaining beads are green. The
13
5
(31)
—
rest of the beads are black. If there are 32 more yellow beads than black beads,
how many beads are green?
5
3
2
—–—=—
5
5
5
21
3
7
—– × — = —– (green)
65
5
13
6
3
18
—– × — = —– (black)
13
5
65
18
2
8
— – —– = —–
65
5
65
8 units→ 32 beads
1 unit→ 4 beads
21 units→ 84 beads
84 beads
(32)A man typed 200 words in 15 min and another 320 words in 25 min. Find the
average number of words he typed per minute.
200 + 320 = 520
He typed a total of 520 words.
15 + 25 = 40
He took 40 minutes to type 520 words.
520 Г· 40 = 13
He typed an average of 13 words per minute.
13 words
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Review 1
(33)
A book and 15 pens cost $40.
(a) If the book cost $x, what is the cost of each pen in terms of x?
(b) If the book cost $25.75, how much is each pen?
(a) Cost of 15 pens= $40 – $ x
= $(40 – x)
Cost of 1 pen = $(40 – x) ÷ 15
( 4015– x )
= $  ———
(b) Cost of 1 pen
= $ —————
= $0.95
40 – 25.75
(    
)
15
(a) $
40 – x
(———
)
15
(b) $
0.95
2
3
(34)A bag cost $36. During a sale, it was sold at — of the usual price. Devi bought 3
such bags during the sale. She used her store card and got a further 5% discount
on the bags. How much did she pay altogether?
2
— × $36 = $24
3
$24 Г— 3 = $72
$72 Г— 95% = $68.40
$68.40
Review 1
65
Section C
For each of the following questions, show your working clearly and write your
answer in the space provided.
(35)Jonathan had some stamps. His friend then gave him half the number of stamps
Jonathan had at first. Jonathan then had 54 stamps. How many stamps did he have
at first?
Before
After
54
3 units в†’ 54 stamps
54
3
1 unit → —– = 18 stamps
2 units в†’ 18 Г— 2 = 36 stamps
He had 36 stamps at first.
1
-full, its mass is
(36)The mass of a bottle completely filled with oil is 5 kg. When it is —
4
1.4 kg. Find the mass of the empty bottle.
Mass of bottle when full
1
Mass of bottle when 4 full
5 kg – 1.4 kg = 3.6 kg
3 units в†’ 3.6 kg
  1 unit → 1.2 kg
Mass of empty bottle= 1.4 – 1.2
= 0.2 kg
66
Review 1
(37)Find the area of the shaded triangle.
7 Г— 5 = 35
1
— × 4 × 5 = 10
2
1
— × 1 × 7 = 3.5
2
1
—×5×2=5
2
Area of shaded triangle= 35 – (10 + 3.5 + 5)
= 35 – 18.5
= 16.5 cm2
1 cm
1 cm
(38)(a) Draw a triangle ABC in which BC 5 7 cm,  AB 5 5 cm and ABC 5 55°.
Line BC is given as shown.
(b) From the figure you have drawn, measure оЂЇACB.
A
5 cm
55В°
B
7 cm
C
оЂЇACB = 45В°
Review 1
67
(39)Miss Ang buys some sweets. If she gives her pupils 3 sweets each, she will have
12 sweets left. If she gives them 4 sweets each, she will need 24 more.
(a) How many pupils are there?
(b) How many sweets does she have?
Number of
pupils
Number of sweets
If 3 sweets each If 4 sweets each
30
30 Г— 3 = 90
90 + 12 = 102
30 Г— 4 = 120
120 – 24 = 96
вњ—
36
36 Г— 3 = 108
108 + 12 = 120
36 Г— 4 = 144
144 – 24 = 120
вњ“
A passenger travelled 41.8 km by taxi. How much did the passenger pay using
(40)
the charges given below?
First 1 km or less
$2.80
Every 385 m thereafter or part thereof
$0.20
First 1 km = $2.80
Remaining distance= 41.8 – 1
= 40.8 km
= 40 800 m
40 800
——— = 105 r 375 ≈ 106
385
106 Г— $0.20 = 106 Г— 20Вў
= 2120Вў
= $21.20
$2.80 + $21.20 = $24
The passenger paid $24.
68
Review 1
(41)John had a total of 300 coins in a box. 40% of them were foreign coins and the
rest were local coins. He gave away 10% of the foreign coins.
(a) How many foreign coins did John have at first?
(b) How many coins are left in the box?
40
100
(a) —– × 300 = 120
John had 120 foreign coins at first.
10
100
(b) —– × 120 = 12
John gave away 12 coins.
300 – 12 = 288
288 coins are left in the box.
(42)A Science club had 63 members last year.  The ratio of the number of boys to the
number of girls in the club then was 5 : 4.  This year, 2 new boys and 5 new girls
joined the club. What was the ratio of the number of boys to the number of girls
this year?
Total units= 5 + 4
=9
9 units в†’ 63 members
63
9
s 1 unit → —– = 7 members
5 units в†’ 7 Г— 5 = 35 members (boys)
4 units в†’ 7 Г— 4 = 28 members (girls)
Number of boys this year= 35 + 2
= 37
Number of girls this year= 28 + 5
= 33
The ratio of the number of boys to the number of girls this year was 37 : 33.
Review 1
69
(43)A calculator and a watch cost $70. A calculator and a computer table cost $250.
The computer table cost 5 times as much as the watch.
(a) Find the cost of the watch.
(b) Find the cost of the calculator.
Cost of
calculator
Cost
of
calculator
Cost of computer table
$250 – $70
= $180
Cost
of
watch
(a)4 units в†’ $180
( 1804 )
  1 unit → $  —– = $45
The cost of the watch is $45.
(b) $70 – $45 = $25
70
The cost of the calculator is $25.
Review 1
(44)The figure below is not drawn to scale. ABC is an equilateral triangle and ACDE is
a rhombus. оЂЇADE 5 40В°.
(a) Find оЂЇACD.
(b) Find оЂЇAEB.
E
A
B
C
D
(a) Since AE = DE, ADE is an isosceles triangle.
оЂЇDAE = оЂЇADE = 40В°
AED = 180° – 40° – 40°
= 100В°
оЂЇACD = оЂЇAED = 100В°
(b) CAE= 180° – 100°
= 80В°
оЂЇBAC= 60В°
оЂЇBAE= 60В° + 80В°
= 140В°
Since BA = AC and AC = AE, BA = AE and ABE is an isosceles triangle.
Review 1
оЂЇAEB
= (180° – 140°) ÷ 2
= 40В° Г· 2
= 20В°
71
1
(45)The mass of a bag of prawns is 3.45 kg. The mass of a bag of carrots is —
of the
3
mass of the bag of prawns. Rahayu buys 4 bags of prawns, 2 bags of carrots and 3
bags of tomatoes. The total mass of the bags is 23 kg. What is the mass of each
bag of tomatoes?
Mass of a bag of prawns = 3.45 kg
Mass of 4 bags of prawns= 3.45 Г— 4 = 13.8 kg
Mass of a bag of carrots = 3.45 Г· 3 = 1.15 kg
Mass of 2 bags of carrots= 1.15 Г— 2 = 2.3 kg
Mass of 4 bags of prawns and 2 bags of carrots = 13.8 + 2.3 = 16.1 kg
Mass of 3 bags of tomatoes= 23 – 16.1
= 6.9 kg
Mass of a bag of tomatoes = 6.9 Г· 3
= 2.3 kg
72
Review 1
(46)Mrs Phua bought some pots and bowls. She paid $116 for them. The pots cost
$12 each and a bowl was $5 cheaper than a pot. Mrs Phua bought 3 more bowls
than pots.
(a) How many pots did Mrs Phua buy?
(b) How many bowls did Mrs Phua buy?
Cost of 1 bowl= $12 – $5
= $7
Cost of 3 bowls= $7 Г— 3
= $21
Cost of 1 bowl and 1 pot= $7 + $12
= $19
(a) $116 – $21 = $95
$95 Г· $19 = 5
Mrs Phua bought 5 pots.
(b) 5 + 3 = 8
Review 1
Mrs Phua bought 8 bowls.
73
(47)The graph below shows the number of people who went to a cinema in a
particular week.
800
700
600
Number 500
of
400
people
300
200
100
Mon Tue Wed Thu Fri
Days of the week
Sat
Sun
(a) What was the average number of people who went to the cinema per day
during that week?
(b) The average number of people who went to the cinema in that week and the
following week was 450. How many more people went to the cinema in the
following week?
(a) Total number of people= 200 + 500 + 200 + 300 + 200 + 600 + 800
= 2800
Average number of people= 2800 Г· 7
= 400
(b) Total number of people for two weeks= 450 Г— 14
= 6300
Number of people who went in the following week= 6300 – 2800
= 3500
74
3500 – 2800 = 700
700 more people went to the cinema in the following week.
Review 1