Parent WorkshopMathematics4 April 2018

Overview

• Problem solving process

• Common skills tested in PSLE

• Types of problem tested in PSLE

Mathematics Framework

Concepts

Numerical

Algebraic

Geometrical

Statistical

Probabilistic

Analytical

Numerical

calculation

Algebraic

manipulation

Spatial visualisation

Data analysis

Measurement

Use of mathematical

tools

Estimation

Reasoning,

communication and

connections

Thinking skills and

heuristics

Application and

modelling

Beliefs

Interest

Appreciation

Confidence

Perseverance

Mathematical Problem Solving

Monitoring of one’s own

thinking

Self-regulation of learning

Understand

Plan/Devise

Do/Carry Out

Check

Understand• Students can use the following to help them

to understand the problem better.

- Models

- Pictures

- Tables

Plan for a strategy • Students can use one or a combination of the

strategies below :

- Models : Comparison, part-whole

- Guess and Check

- Assumption

- Branching

- Before and After and many more ….

- A combination of a few strategies

Do / Carry out• Students will work out the

solution by apply the strategy planned.

- For effective problem solving, students must have good mastery of cognitive skills / basic algorithms (eg: 4 operation of whole numbers, fractions, decimals, conversion etc) is essential.

Models / Tables / Pictures

Equations

Working

Statement

Check• Students need to check if the answer they

obtained make sense

• They need to check the reasonableness of their answer

Grouping / Sharing Concept

A B C D D C B A A B C D D C B A …..?

1st 16th 69th

There are 8 alphabets in 1 group.

There are altogether 69 alphabets. What is

the 69th alphabet?

69 ÷ 8 = 8 R 5

.R1 R2 R3 R4 R5

So the 69th alphabet is

A B C D D

D

4 teams of students washed cars for charity. They

collected $10 for washing a small car and $15 for a

big car. The table shows the number of cars

washed by 3 of the teams.

Team D washed as many cars as Team A but

collected $30 more How many big cars did Team D

washed?

Teams Number of cars washed

small big

A 15 5

B 11 9

C 8 10

A collected 15 x $10 + 5 x $15 = $225

Number of cars washed by Team A = 15 + 5 = 20

D collected $225 + $30 = $255

Number of cars washed by Team D = 20

Assume only small cars are washed

20 x $10 = $200

$255 - $200 = $55

…………………..20

$10 $10 $10 $10 $10 $10 $10

$5 $5 $5 $5 $5

$55 ÷ $5 = 11There are 11 big cars.

The average height of a group of children was

139.4 cm.

When Mr Tan measured and recorded the height

of these children, he wrongly recorded one child’s

height as 192 cm when it should have been 129

cm. As a result, Mr Tan calculated the average

height as 142.4 cm.

How many children were there in the group?

Child 1 Child 2 Child 3, ……., Child(x-1) Child x

Actual: 139.4 139.4 139.4, …………, 139.4 139.4

Wrong : 142.4 142.4 142.4, …………., 142.4 142.4

3 3 3 3 3

Excess : 192 – 129 = 63

63 ÷ 3 = 21

There were 21 children in the group.

Models

• 4 girls shared the cost of a cake equally. When calculating

for each share, one of the girls made a mistake by dividing

the cost of the cake by 3 instead of 4. Each girl paid $2.40

more than her share. What should be the correct amount for

each share?

$2.401 unit = $2.40

3 units = $2.40 x 3 = $7.20

The correct amount for each share was $7.20.

• Mr Lee baked 185 more chicken than tuna pies. After

selling 3

5of the chicken pies and half of the tuna pies,

he had 146 pies left. How many tuna pies did he sell?

Chicken :

Tuna

185

3

5=

6

10

2

5x 185 = 74

9 units = 146 – 74 = 72

1 unit = 72 ÷ 9 = 8

5 units = 8 x 5 = 40

Amount of drink : 7.2

3 Large

bottles

5 small

bottles0.5 0.3

1

small

1 large bottle

Difference : 0.3 + 0.5 = 0.8

1 large bottle can hold 0.8 litres more than 1

small bottle

Visualisation

• 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

John used 1-cm cubes to build the structure below.

The top view has been drawn in the square grid below.

Draw the front and side views of the structure in the grids

below.

Top view

side view

Front view

Pattern

True/ False / Not Possible to tell

Statement True False Not possible

to tell

Total mass of D and E is

24 kg.

Mass of D is greater than

the total mass of A and B.

Average mass of the 5

boxes is 14.4 kg.

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In Mariam’s aquarium, there are swordtails and guppies.

25% of the fishes are swordtails. She then buys an equal

number of swordtails and puts them into the aquarium.

Statement True False Not possible

to tell

Percentage of guppies will

remain the same.

Percentage of swordtail

increased by 50%.

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Parents’ Workshops 2018

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