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 Beliefs Monitoring of one’s own Interest Appreciation thinking Confidence Self-regulation of learning Perseverance Mathematical Numerical calculation Problem Reasoning, Algebraic Solving communication and manipulation connections Spatial visualisation Data analysis Thinking skills and Concepts Measurement heuristics Numerical Use of mathematical Application and Algebraic tools modelling Geometrical Estimation Statistical Probabilistic Analytical

Understand Plan/Devise Check Do/Carry Out

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

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 …..? 1 st 16 th 69 th There are 8 alphabets in 1 group. There are altogether 69 alphabets. What is the 69 th alphabet? 69 ÷ 8 = 8 R 5 R1 R2 R3 R4 R5 . A B C D D So the 69 th alphabet is 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. Teams Number of cars washed small big A 15 5 B 11 9 C 8 10 Team D washed as many cars as Team A but collected $30 more How many big cars did Team D washed?

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 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 3 3 3 3 3 Wrong : 142.4 142.4 142.4, …………., 142.4 142.4 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 3 selling 5 of the chicken pies and half of the tuna pies, he had 146 pies left. How many tuna pies did he sell?

3 5 = 6 Chicken : 10 185 2 5 x 185 = 74 Tuna 9 units = 146 – 74 = 72 1 unit = 72 ÷ 9 = 8 5 units = 8 x 5 = 40

Amount of drink : 7.2 3 Large 5 small 1 0.3 0.5 small bottles bottles 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 C D B 10cm E 6 cm A 8 cm F

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 one week after the workshops.