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Hougang Primary School
Mathematics Department
Parent Workshop 2016
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Types of PSLE Questions
Computation
cccc
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Example 1
1 + 2 + 3 + 4 + …….. + 94 + 95 + 96 + 97
When the first 97 whole numbers are
added up, what is the digit in the ones
place of this total?
(1) 1
(2) 2
(3) 3
(4) 8
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1 + 2 + 3 + 4 + …….. + 94 + 95 + 96 + 97
1 + 2 + 3 + 4 + …….. + 94 + 95 + 96 + 97
1 + 2 + 3 + 4 + …….. + 94 + 95 + 96 + 97
1 + 2 + 3 + 4 +5 …+ 50+….. + 94 + 95 + 96 + 97
100
100
100
= 100 x 47 + 1 + 2 +50
= 4700 + 53
=4753
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Example 1
1 + 2 + 3 + 4 + …….. + 94 + 95 + 96 + 97
When the first 97 whole numbers are
added up, what is the digit in the ones
place of this total?
(1) 1
(2) 2
(3) 3
(4) 8
Ans : (3)
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Example 2
A repeated pattern is formed using the numbers
1 and 0. The first 18 numbers are shown below.
1 0 1 0 1 1 1 0 1 0 1 1 1 0 1 0 1 1
1st 19th
What is the sum of the first 100 numbers?
(1) 60
(2) 64
(3) 66
(4) 68 2013 PSLE
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There are 6 numbers in 1 group.
There are altogether 100 numbers.
How many groups are there? What is the
remainder?
100 ÷ 6 = 16 R 4
.
R1 R2 R3 R4
1 0 1 0
1 0 1 0 1 1 1 0 1 0 1 1 1 0 1 0 1 1
1st 18th
Sum of each group ------------1 + 0 + 1 + 0 + 1+ 1 = 4
Sum of 100 numbers ---------- 4 x 16 + 1 + 1 =66
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Example 3
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Other computation questions Round off 70.171 to the nearest tenth.
Find the value of 4.8 + 0.29.
Express 1090 cm in m
A solid cuboid of height 10 cm has a square base of
side 3 cm. What is its volume?
Zaleha bought 1.2kg of grapes. 100 g of grapes cost
70 cent. How much did she pay?
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Tips to nail the computation
questions
Firm foundation in number bonds.
Must know the multiplication tables very well.
Encourage children to use mental sum tricks
Example:
0.46 x 70 = 0.46 x 7 x 10
= 3.22 x 10
= 32.2
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Types of PSLE Questions
Scale reading
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Three containers with some water are shown below.
Which container has the most water?
160 ml 150 ml 200 ml
Container C contains the most water
50 20
=500ml
0.1
or
100
ml
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Concepts tested along with
Procedures
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A number when divided by 30 gives a remainder of 8.
Which of the following can be added to the number to
change it to a multiple of 6?
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Spatial Visualisation
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Question 1
In the figure below, ABDF and BCEF are rectangles and
CDE is a straight line. AB = 6 cm, AF = 8 cm and
BF = 10 cm. Find the length of BC
10cm
B
A
C
D
E
F
6 cm
8 cm
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Question 2
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MQN is an equilateral triangle
QPM is an isosceles triangle
MPQ = ( 180 – 30 ) ÷2 = 75
MPN = 75 x 2 = 150
60o
60o
60o
30o
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Question 4
In the figure below, a rectangular piece of paper is folded
at 2 of its corners A and C as shown. Find ABC
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Practical Questions
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In the square grid below, PQ and QR are straight lines.
(a) Measure and write down the size of PQR
(b) PQ and QR form 2 sides of a trapezium PQRS. PS is
parallel to QR. PS is twice the length of QR. Complete
the drawing of the trapezium PQRS.
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Word Problems
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Understand
Plan/Devise
Do/Carry Out
Check
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Understand • What am I given? (information , data)
• What am I asked to find?
• How can I make sense of the information
given to me? (Keywords, models, tables )
Plan/Devise • What strategy should I use?
• Have I solved similar problems before?
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Strategies / Heuristics
Working backwards
Make a table
Systematic listing
Pattern Recognition
Assumption
Guess and Check
Model Drawing
Before and After concept
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Do/Carry Out
• Are my steps accurate?
• Are there traps that I need to be alert of?
• Have I used all the information?
• Do my steps make sense?
Check • Does my answer make sense?
• Did I answer the question?
• Could this problem be solved in a simpler
way?
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Question 1
Meng sold a total of 368 large and small durians at
the prices shown below and collected $2760. How
many large durians did Meng sell?
Durian for Sale
Large $9 Small $5
2 totals given
Plan :
Assumption
Guess & Check
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Assumption
Assume all are small durians.
Cost of durians ----- 368 x $5 = $1840
Difference between actual cost and assumed cost
----- $2760 - $1840 = $920
$5 $5 $5
………
No of large durians ------- $920 ÷ $ 4 = 230
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Question 2
Robin bought some pens for $42. He bought the same
number of rulers for $22. Each pen cost $2 more than
each ruler.
How many rulers did Robin buy?
Same number
of rulers
1 Pen is more
expensive than
1 ruler
Plan :
Differences
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Since the number of rulers and pens are the
same
No of
pens:
No of
rulers :
$42
$22
$42 - $22 = $20
$20 ÷ $2 = 10
Robin bought 10 rulers.
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Question 2
160 more
chickens than
duck
Plan : model
drawing
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ducks
chickens
S
S
S
L
S S L L
160
80
S
80
L
3 units + 80 ------- 230
3 units -------- 230 – 80 = 150
1 units -------- 150 ÷ 3 = 50
There are 50 ducks left.
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Question 3
The ratio of the number of books to the number of files
was 7 : 2.
When 20 books and 25 files were added, the ratio
became 2 : 1.
How many files were there at first?
2 different
types of units
Plan :
units and parts
Before and after
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Units and Parts
Books Files
Before
After
7 units + 20 ----------- 2 parts
2 units + 25 ----------- 1 part
7 units 2 units
+20 books +25 files
2 parts 1 part
(
)
4 units + 50 ----------- 2 parts
7 units +20 ---------- 4 units + 50
X2
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7 units +20 ---------- 4 units + 50
3 units ---------- 50 – 20 = 30
1 unit --------- 30 ÷ 3 = 10
2 units -------- 10 x 2 = 20
There were 20 files at first.
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Question 5
Ishak uses rods to form figures that follow a pattern. The
first four figures are shown below.
How many rods would he use for Figure 30?
Figure Number Number of rods used
1 10
2 15
3 18
4 23
Numbers
increase at
regular
intervals
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Figure Number Number of rods used
1 10
2 15
3 18
4 23
5 23 + 3 = 26
6 26 + 5 = 31
7 31 + 3 = 34
…… …….
30 127
+ 5
+ 3
Systematic Listing
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Grouping
Figure Number Number of rods used
1 10
2 15
3 18
4 23
+2 +8
Number of figure from Figure 4 to Figure 30
= 30 – 4 = 26
Number of increases of 8 rods from Fig 4 to 30
= 26 ÷ 2 = 13
Number of rods in Figure 30
= 23 + 13 x 8 = 127
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Final Note
Regular revision by re-doing questions that your child has
done wrongly.
Encourage your child to simplify the problem by drawing
models (pictures) or presenting the information in a
table.
Ensure adequate and productive practice.
Provide opportunities for time-based practices.
Ground the basics first before moving on to challenging
problems.
Remind your child to start with the simpler questions and
move on if he is stuck.