Model Drawing 1

Recap question

Question 1: 

There were 150 girls and 208 boys at a carnival. How many children were there altogether?

1. 58
2. 352
3. 358
4. 385

Solution: 

We can draw a bar model to represent the numbers in a question. A longer bar represents a greater value while a shorter bar represents a smaller value. In this question, the bar representing the number of boys will be longer while the bar representing the number of girls will be shorter.

\(150 + 208 = 358\)

Answer:

(3) 358

Question 2: 

A fruit seller has a total of 295 apples. 104 of the apples are green while the rest of the apples are red. How many red apples does he have?

1. 111
2. 191
3. 199
4. 399

Solution: 

\(295 - 104 = 191\)

Answer:

(2) 191

1. Part-Whole Models - 2 Step

2-step problems are problems that require 2 operations to solve them. We can draw a bar model to represent each operation or a combined bar model to represent both operations to help us.

They can include two additions, two subtractions or a mix of both.

Example 1:

At a bookshop, there are 80 red pens, 134 blue pens and 67 green pens. How many red and blue pens are there?

Solution:

\(80 + 134 = 214\)

Answer:

214 pens

Example 2:

At a bookshop, there are 80 red pens, 134 blue pens and 67 green pens. How many pens are there altogether?

Solution: 

Add the number of red, blue and green pens to find the number of pens altogether.

\(214 + 67 = 281\)

Answer:

281 pens

Question 1: 

At a football match, there are 430 adults, 126 girls and 225 boys. How many people are there at the football match altogether?

1. 351
2. 556
3. 771
4. 781

Solution: 

This model has 3 parts: adults, girls and boys. The adults will have the longest bar, followed by the boys, then the girls. 

\(\begin{align}​​ 430 + 126 &= 556 \\[2ex] 556 + 225 &= 781 \end{align}\)

Answer:

(4) 781

Question 2: 

There were 474 pages in a storybook. Gina read 124 pages on Saturday and 150 pages on Sunday. 

1. How many pages did she read on both days together?

Solution: 

\(124 + 150 = 274\)

Answer:

274

2. How many pages of the storybook were left unread?

Solution: 

\(474 - 274 = 200\)

Answer: 

200

OR

Alternatively, we can also subtract the total number of pages read on Saturday and Sunday from the total number pages as follows:

\(\begin{align}​​ 474 - 124 &= 350 \\[2ex] 350 - 150 &= 200 \end{align}\)

Answer:

200

Question 3: 

Choose the correct model that best represents the following:

There were overall 380 red beads, yellow beads and blue beads in a bag. 120 beads were red and 180 beads were yellow. How many beads were blue?

Answer:

(1)

Question 4:

Jerald had 160 stamps in his album. He gave 40 stamps to his sister and 35 stamps to his friend.

1. How many stamps did he give away altogether? 

1. 5
2. 15
3. 75
4. 85

Solution: 

\(40 + 35 = 75\)

Answer:

(3) 75

2. How many stamps was Jerald left with?

1. 85
2. 95
3. 115
4. 235

Solution: 

\(160 - 75 = 85 \)

Answer:

(1) 85

Question 5: 

There are 800 people at a stadium. 242 of them are boys and 136 of them are girls. The rest of them are adults. How many adults are there?

1. 378
2. 422
3. 432
4. 532

Solution: 

\(\begin{align}​​ 242 + 136 &= 378 \\[2ex] 800 -  378 &= 422 \end{align}\)

Answer:

(2) 422

Challenge yourself!

Question 1: 

There were 105 jelly beans in a jar. Afiq took out 23 jelly beans to give to his brother.    He then bought another 45 jelly beans and put them in the jar. 

1. How many jelly beans were left in the jar after Afiq gave 23 jelly beans to his brother?
2. 22
3. 72
4. 82
5. 128

Solution: 

\(105 - 23 = 82\)

Answer:

(3) 82

2. How many jelly beans were left in the jar in the end?
3. 37
4. 123
5. 127
6. 150

Solution:

\(82 + 45 = 127\)

Answer:

(3) 127
 

In this article, we learned about Model Drawing: 

Part-Whole Models (2 step)

• 2-step problems are problems that require 2 operations to solve them. 
  • We can draw a bar model to represent each operation or a combined bar model to represent both operations to help us.