1. North View Primary School 1 Model Drawing (Basics)

2. North View Primary School Models are pictorial representations (i.e. bar diagrams) drawn to represent the data in a problem sum. It allows us to visualize the relationship between the parts and/or whole in a problem sum. Model Drawing

3. North View Primary School Problem Solving Tips Read the question carefully. Underline important information. Transfer the information/data into a model. Use a ? to represent the unknown data. Label the model with names of the people/things in the question.

4. North View Primary School Types of Models Part-whole (i.e. for one person) Ali Don Comparison (i.e. for comparison between two people) 30 stamps ? ? Don has as many stamps as Ali.

5. North View Primary School Part-whole model A box of cereal costs $7. How many such boxes of cereal can Kelly buy with $42? $42 $7 $42 ÷ $7 = 6 She can buy 6 boxes of cereal. ? boxes

6. North View Primary School Comparison Model Bala has the amount of money Alyssa has. Bala has thrice the amount of money Catherine has. If the total amount of money they have is $50, how much money does Alyssa have? B C A $50 ?

7. North View Primary School 10 units  $50 1 unit  $50 ÷ 10 = $5 B C A $50 ? 6 units  $5 x 6 = $ 30 She has $30.

8. North View Primary School Other models ‘Stack Up’ Model ‘Constant Difference’ Model Before & After Model These models are improvisation of the part- whole and/or comparison models.

9. North View Primary School ‘Stack Up’ Model 2 dictionaries and 4 novels cost $90. Each dictionary cost thrice as much as each novel. How much did each dictionary cost? D $90 ? N D N N N

10. North View Primary School N D $90 ? D N N N 10 units  $90 1 unit  $90 ÷ 10 = $9 3 units  $9 x 3 = $ 27 Each dictionary cost $27.

11. North View Primary School ‘Constant Difference’ Model There was 14 kg of rice in Box A and 2 kg of rice in Box B. Tommy added an equal amount of rice into each box. Now there are 5 times as much rice in Box A as in Box B. How much rice is there in Box A in the end? Box A 14 kg Box B 2 kg12 kg

12. North View Primary School There is 15 kg of rice in Box A. 4 units  12 kg 1 unit  12 kg ÷ 4 = 3 kg Box A 14 kg Box B 2 kg12 kg 14 kg – 2 kg = 12 kg 5 units  3 kg x 5 = 15 kg ?

13. North View Primary School Before & After Model John ? Ivan John and Ivan had an equal number of sweets. After John gave away 36 sweets, Ivan had 5 times as many stamps as John. How many stamps did Ivan have? 36 John Ivan Before After

14. North View Primary School John Ivan ? 36 Ivan had 45 sweets. 4 units  36 1 unit  36 ÷ 4 = 9 5 units  9 x 5 = 45