Parents Seminar on Heuristics at Chongfu School

Help Your Child in Problem-Solving Heuristics
Dr Yeap Ban Har
banhar.yeap@pathlight.org.sg
Marshall Cavendish Institute
Singapore
www.banhar.com
Photo Credit: Students solving a mathematics problem using draw-a-diagram heuristic at Da Qiao Primary School.

Heuristics are rule of thumb that students can use to handle a problem when the solution is not obvious.

The problems used in the presentation are from PSLE Examination Questions Years 2006 – 2010 Mathematics published by Educational Publishing House Pte Ltd.

PSLE 2006 – 2010 Page 13 Question 45

Photo Credit: Primary 2 students at Woodlands Primary School using manipulatives to do multiplication and division.

1.2 m x 42 = 50.4 m
43 – 6 = 37 There were 36 spacing
50.4 m ÷ 36 = 1.4 m
The new spacing was 1.4 m.

Guess when each tried taking 11
33 Last girl had 11 sweets

List 1 List 2
11 + 6
22 + 6
33 + 6
44 + 6
55 + 6
66 + 6
16 + 25
24 + 25
32 + 25
40 + 25
48 + 25
56 + 25

List 1 List 2
11 + 6
22 + 6
33 + 6
44 + 6
55 + 6
66 + 6
77 + 6
88 + 6
99 + 6
16 + 25
24 + 25
32 + 25
40 + 25
48 + 25
56 + 25
64 + 25
72 + 25
80 + 25

3 x ? = 2 + 25
? = 9
There were 10 girls.
There were 9 x 11 + 6 = 8 x 10 + 25 = 105 sweets altogether.

There were 10 girls.
11m + 6 = 8(m + 1) + 25
m = 9
Alternate Method
8n + 25 = 11(n – 1) + 6
n = 10

women
30
men
There were 4 x 30 = 120 men and women at first.

Photo Credit: Primary 2 students at Woodlands Primary School using the interactive board to learn independently and collaboratively.

Method 1
Azlan, Bala, Chris, Darren
Azlan, Bala, Chris, Enling
Azlan, Bala, Darren, Enling
Azlan, Chris, Darren, Enling
Bala, Chris, Darren, Enling,
Method 2
Selecting 4 persons from a group of 5 is the same as to leave out one person from a group of 5.
There are 5 ways to leave out 1 person from a group of 5.
Hence there are 5 ways to select 4 prefects from a group of 5 students.

1 third
= 4/12
remainder
= 5/12
1 fourth = 3/12
38 + 57 = 95
2 fifths  38 peaches
2 fifths  38 peaches
1 fifth  19 peaches
3 fifths  3 x 19 pears = 57 pears
5/12  95 fruits
1/12  19 fruits
There were 12 x 19 fruits or 228 fruits.

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Parents Seminar on Heuristics at Chongfu School

by Jimmy Keng on Mar 06, 2011

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