# Model Drawing 1

In this article, we will learn about Model Drawing:

- Part-Whole Models - 2 step

**Recap Question**

**Question 1: **

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

- 58
- 352
- 358
- 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?

- 111
- 191
- 199
- 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 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?

- 351
- 556
- 771
- 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.

- How many pages did she read on both days together?

**Solution: **

\(124 + 150 = 274\)

**Answer:**

274

- 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.

- How many stamps did he give away altogether?

- 5
- 15
- 75
- 85

**Solution: **

\(40 + 35 = 75\)

**Answer:**

(3) 75

- How many stamps was Jerald left with?

- 85
- 95
- 115
- 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?

- 378
- 422
- 432
- 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.

- How many jelly beans were left in the jar after Afiq gave 23 jelly beans to his brother?

- 22
- 72
- 82
- 128

**Solution: **

\(105 - 23 = 82\)

**Answer:**

(3) 82

- How many jelly beans were left in the jar in the end?

- 37
- 123
- 127
- 150

**Solution:**

** **

\(82 + 45 = 127\)

**Answer:**

(3) 127

In this article, we learnt 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.