Parent Workshop Mathematics 4 April 2018 Overview Problem solving - - PowerPoint PPT Presentation

Parent Workshop

Mathematics 4 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

• peration of whole numbers,

fractions, decimals, conversion etc) is essential. Models / Tables / Pictures Equations Working Statement

Check

• Students need to check if the answer they
• btained 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 = 11 There are 11 big cars.

The average height of a group of children was 139.4 cm. When Mr Tan measured and recorded the height

• f 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?

$2.40

1 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 5 of 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 5 x 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 bottles 0.5 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.

√ √ √

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%.

√ √

Parents’ Evaluation and Feedback For Parents’ Workshops 2018

• Please scan the QR Code or use the link to give us your

valuable feedback. Thank you.

https://tinyurl.com/y9m65zxr

Parents’ Workshops 2018

• Presentation

slides will be available on our school website within

• ne

week after the workshops.