Using The Model Method to Solve Word Problems

Dr Yeap Ban HarMarshall Cavendish Institute

Singapore

Slides are available at www.banhar.blogspot.com

Collegio Dagoberto Godoy, Santiago de Chile

The Curriculum (Ministry of Education 2006)

The Curriculum (Ministry of Education 2006)

emphasis thinking

emphasis visualization

122 xx

Experiencing Singapore Math

Experiencing Singapore Math

Experiencing Singapore Math

Kyla

Jake $9

$28

?

?$28 – $9 = $19

Kyla has $19.

Ming

Naomi

48

48 ÷ 4 = 12

Ming has 36 candies.

3 x 12 = 36

apples

15

3 units 1518 units 6 x 15 = 90

There are 90 fruits in the basket.

Method 1 3 units 1518 units 6 x 15 = 60 + 30 = 90

Method 2 3 units 15 1 unit 518 units 18 x 5 = 50 + 40 = 90

18 units 6 x 15 = 3 x 30 = 90

18 units 18 x 5 = 180 ÷ 2 = 90

$18

$24 ÷ 3 = $8 Allan’s allowance = 4 x $8 = $32

$6

Mon

Tue $3

Wed $3 $3

Thu $3 $3

$100

$100 – 6 x $3 = $82

$82 ÷ 4 = $20.50

$20.50 + 3 x $3 = $29.50

She saved $29.50 on Thursday.

$3

adults

children

2 units 380 – 260 = 120 1 unit 60 260 – 60 = 200200 + 200 = 400 400 people left at lunchtime.

apples

oranges 90

pears 15

38

apples

oranges 90

pears 15 23

apples

oranges ?

pears 15

90 + 15 = 1055 units

1 unit 105 ÷ 5 = 21

23

There were (21 + 21 + 23) apples, hence oranges.There were 44 oranges used.

apples

oranges 90

pears

38

What if we have drawn 38 to be much longer?

15

apples

oranges 105

pears

38

What if we have drawn 38 to be much longer?

We still get 5 units 105

One other way to solve it …

Number of oranges left = xNumber of apples left = 2xNumber of pears left = 2x – 15

x + 2x + 2x – 15 = 905x = 105 x = 21

Number of pears left = 2 x 21 – 15 = 27Number of pears at first = 38 + 27 = 65

Number of oranges at first = 65Number of oranges used = 65 – x = 65 – 21 = 44

342

18%

24%

76%

76% 342

1% 4.5

100% 450

Mr Wong had 450 books at first.

Jane + Xueling Siti

Xueling + Siti (64)Jane (16)

(24)

(24 – 16) units = 8 units

(40)

8 units = 14 shells

40 units = 5 x 14 shells

40 units = (50 + 20) shells

Xueling collected 70 shells.

This problem requires the ability to visualize.

b

d

xx + b + d = 180

c

e y y + c + e = 180

By the same logic:• x + b + d = 180• y + c + e = 180• z + a + d = 180• v + b + e = 180• w + a + c = 180

a

b

cd

e x y

z

v

w

2a + 2 b + 2c + 2d + 2e + x + y + z + v + w = 5 x 180

x + y + z + v + w = 3 x 180

Hence, a + b + c + d + e = 180

Using The Model Method to Solve Word Problems

Dr Yeap Ban HarMarshall Cavendish Institute

Singapore

Slides are available at www.banhar.blogspot.com

Using The Model Method to Solve Word Problems

Slides are available at www.banhar.blogspot.com

Mani has 245 ten-cent coins and

455 five-cent coins. Nina has

165 ten-cent coins and 135 five-

cent coins. After Mani gives

Nina some coins, of Mani’s

coins are ten-cent ones and the

ratio of the number of Nina’s

five-cent coins to the number of

her one-cent coins is 3 : 2.

They have only five-cent and

one-cent coins.

5

1

Find the number of coins Mani gives to Nina.

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