SingaporeMath in Action 3

singaporemathinaction

mathematical problem solving

Yeap Ban HarNational Institute of Education

Singapore

www.banhar.com

Session 3

Problem 1How many paper clips are there in the box on your table?


Problem 2Arrange the cards so that you can do the card trick shown to you.


Problem 3How many three-fourths are there in 1 whole?


How many three-

fourths are there in one

whole?

Ateneo Grade School, Manila

Problem 4Give a 3-digit number and a 2-digit number so that the difference is 3.


-

3

Problem 5Use one set of digit tiles to make a correct addition sentence.


+

Problem 6Use one set of digit tiles to make a correct addition sentence.


+

Problem 7Use one set of digit tiles to make a correct multiplication sentence.


x

Solutions from Participants• 45 x 2 = 90 • 18 x 2 = 36 • 16 x 3 = 48 • 43 x 2 = 86• 13 x 4 = 52• 17 x 2 = 34• 14 x 5 = 70• 26 x 3 = 78• 15 x 6= 90• 29 x 3 = 87

• 34 x 2 = 68• 12 x 5 = 60• 13 x 6 =78• 35 x 2 = 70• 48 x 2 = 96• 16 x 5 = 80• 12x 8 = 96• 15 x 4 = 60• 19 x 2= 38• 27 x 3 = 81

• 15 x 2 = 30• 17 x 4 = 68• 12 x 7 = 84• 19 x 3 = 57

Why are there so few odd products?

Shaping Maths Coursebook 4A

Two Numbers


614

2 units 6144 units 1228

The sum of the two numbers is 1228.


Boys & Girls


342

2 units 342 – 50 = 2921 unit 292 ÷ 2 = 140 + 6 = 146

There are 146 Primary Four boys.

boys

girls 50


Stamps


1775 + 85

After

1 unit 1860 ÷ 4 = 465

At first, Samuel had 465 – 85 = 380 stamps.

Ravi

Samuel


Keys Grade School, Manila

1860

1600 260

240 20

George Polya’sProblem-Solving

Model• Understand


• Plan• Do• Look Back

Think!Can you recall each of the four problem-solving phases when we were solving the problems in the last hour or so?


HeuristicsWhat are some of the methods used to solve the problems? Make a list of heuristics used.


SingaporeMath in Action 3

Education

Transcript of SingaporeMath in Action 3