All the solutions provided in **McGraw Hill Math Grade 3 Answer Key PDF Chapter 4 Lesson 3 Multiply with Arrays** will give you a clear idea of the concepts.

## McGraw-Hill My Math Grade 3 Answer Key Chapter 4 Lesson 3 Multiply with Arrays

**Draw It**

An array has rows of equal length and columns of equal length.

- Make an array on a piece of paper. Arrange the tiles in 4 rows with 3 tiles in each row. Draw the array.
- Count. What is the total number of tiles? ____
- Turn your paper. There are now ____ rows with ___ tiles in each row.

Draw what the array looks like now. - Count. What is the total number of tiles? _____

So, there are the same number of tiles, ____, if you turn the array.

The Commutative Property of Multiplication states that the order in which numbers are multiplied does not change the product.

Answer:

Explanation:

One way:

I drew an array that has 4 rows and 3 columns

The addition sentence that shows the equal rows is

3 + 3 + 3 + 3 = 12

The multiplication sentence that represents the array is 4 x 3 = 12

Another way:

I turned the array and it has 2 rows and 5 columns

The addition sentence that shows the equal rows is

4 + 4 + 4 = 12

The multiplication sentence that represents the array is 3 x 4 = 12.

**Try It**

1. Use tiles to make an array on paper that has 5 rows of 2 tiles. Draw the array.

Write an addition sentence to show equal rows.

___ + ___ + ___ + ____ + ___ = ____

Write a multiplication sentence to represent the array.

2. Turn the array the other way. There are now rows of ____ tiles. Draw the array.

Write an addition sentence to show equal rows.

___ + ___ = ___.

Write a multiplication sentence to represent the array.

____ + ____ = ____

3. Write a multiplication sentence to represent the array.

Answer:

Explanation:

One way:

I drew an array that has 5 rows and 2 columns

The addition sentence that shows the equal rows is

2 + 2 + 2 + 2 + 2 = 10

The multiplication sentence that represents the array is 5 x 2 = 10

Another way:

I turned the array and it has 2 rows and 5 columns

The addition sentence that shows the equal rows is

5 + 5 = 10

The multiplication sentence that represents the array is 2 x 5 = 10.

**Talk About It**

Question 1.

**Mathematical PRACTICE 2 Stop and Reflect** What is the connection between repeated addition and an array?

Answer:

An array is a collection of numbers arranged in a specific manner. This arrangement is either in rows or columns. A Repeated Addition Array is used tofind the total number of similar elements in an array through addition.

Question 2.

How can you use an array to model the Commutative Property?

Answer:

The commutative property of multiplication can be neatly illustrated using an array. An array could be read as rows of, or as columns of. Or the array could be physically turned around to show that rows of has the same number as rows of.

Question 3.

List 3 everyday objects that are arranged in an array.

Answer:

Books, glasses and boxes in house are usually arranged in an array.

**Practice It**

**Draw an array to find the product.**

Question 4.

4 × 2 = ____

Answer:

Explanation:

I drew an array to find the product of 4 x 2

2 + 2 + 2 + 2 = 8

4 x 2 = 8

Therefore, the product is 8.

Question 5.

3 × 5 = ____

Answer:

Explanation:

I drew an array to find the product of 3 x 5

5 + 5 + 5

3 x 5 = 15

Therefore, the product is 15.

**Write an addition sentence and a multiplication sentence to show equal rows.**

Question 6.

___ + ____ + ____ + ____ = _____

____ × ____ = _____

Answer:

5 + 5 + 5 + 5= 20

4 x 5 = 20

Explanation:

The addition sentence that shows equal rows is 5 + 5 + 5 + 5 = 20

The multiplication sentence that shows equal rows is 4 x 5 = 20.

Question 7.

___ + ____ + ____ + ____ = _____

____ × ____ = _____

Answer:

3 + 3 + 3 = 9

3 x 3 = 9

Explanation:

The addition sentence that shows equal rows is 3 + 3 + 3 = 9

The multiplication sentence that shows equal rows is 3 x 3 = 9.

Question 8.

___ + ____ = _____

____ × ____ = _____

Answer:

3 + 3 = 6

2 x 3 = 6

Explanation:

The addition sentence that shows equal rows is 3 + 3 = 6

The multiplication sentence that shows equal rows is 2 x 3 = 6.

Question 9.

**Use the Commutative Property of Multiplication** to write another multiplication sentence for Exercise 8.

____ × ____ = _____

Answer:

2 x 3 = 6

Explanation:

2 x 3 has 2 rows and 3 columns

Change rows to columns to find another sentence

3 rows and 2 columns

Another multiplication sentence for 2 x 3 = 6 is 3 x 2 = 6.

Question 10.

Describe a real-world situation for Exercise 6.

Answer:

Sheela has 4 trays of eggs. Each tray has 5 eggs. How many eggs does Sheela has in all.

Explanation:

Sheela has 4 trays of eggs

Each tray has 5 eggs

The multiplication sentence that solves the problem is 4 x 5

4 x 5 = 20

So, Sheela has 20 eggs in all.

**Apply It**

Question 11.

Marcos has 3 sheets of stickers. Each sheet has 4 stickers on it. Write a multiplication sentence to find how many stickers he has in all.

____ × ____ = _____ stickers

Answer:

Explanation:

Marcos has 3 sheets of stickers

Each sheet has 4 stickers on it

The multiplication sentence is 3 x 4

3 x 4 =

Use repeated addition

4 + 4 + 4 = 12

So, 3 x 4 = 12

Therefore, Macros has 12 stickers in all.

Question 12.

Circle the picture that does not represent an array. Explain.

Answer:

Explanation:

An array is an orderly arrangement (often in rows, columns or a matrix) that is most commonly used as a visual tool for demonstrating multiplication and division. The picture that is circled is not arranged in rows and columns. So, it does not represent an array.

Question 13.

**Mathematical PRACTICE 1 Keep Trying** Draw an array to find the unknown number in the multiplication sentence 6 × = 18.

Answer:

Explanation:

The above drawn array has 6 rows and 3 columns

The multiplication sentence is 6 x 3

6 x 3 = 18

So, the unknown number in the given sentence is 3.

**Write About It**

Question 14.

How can I use an array to model multiplication?

Answer:

An array helps you to understand multiplication by visualising it. It makes sense of your times tables. For example, an array shows that, when multiplying two numbers together, the order of those numbers can be switched around. By way of an example, let’s take a look at two arrays: 2 x 4 and 4 x 2 .

2 x 4 = 8 and 4 x 2 = 8.

### McGraw Hill My Math Grade 3 Chapter 4 Lesson 3 My Homework Answer Key

**Practice**

**Draw an array to find the product.**

Question 1.

5 × 7 = ____

Answer:

Explanation:

I drew an array to find the product of 5 x 7

7 + 7 + 7 + 7 + 7

5 x 7 = 35

Therefore, the product is 35.

Question 2.

6 × 5 = ____

Answer:

Explanation:

I drew an array to find the product of 6 x 5

5 + 5 + 5 + 5 + 5 + 5

6 x 5 = 30

Therefore, the product is 30.

**Write an addition sentence and a multiplication sentence to show equal rows.**

Question 3.

__________

__________

Answer:

2 + 2 + 2 + 2 = 8

4 x 2 = 8

Explanation:

The addition sentence that shows equal rows is 2 + 2 + 2 + 2 = 8

The multiplication sentence that shows equal rows is 4 x 2 = 8.

Question 4.

__________

__________

Answer:

5 + 5 + 5 + 5 + 5 = 25

5 x 5 = 25

Explanation:

The addition sentence that shows equal rows is 5 + 5 + 5 + 5 + 5 = 25

The multiplication sentence that shows equal rows is 5 x 5 = 25.

**Vocabulary Check**

Question 5.

Draw two arrays to model 2 × 3 = 6. Use the arrays to show the meaning of the Commutative Property of Multiplication.

Answer:

Explanation:

The above drawn arrays model of 2 x 3 = 6

The first array has 2 rows and 3 columns

2 x 3 = 6

The second array has 3 rows and 2 columns

3 x 2 = 6

The multiplication sentences 2 x 3 = 6 and 3 x 2 = 6 has same product and represent commutative property of multiplication

So, the arrays show the meaning of commutative property of multiplication.

**Problem Solving**

Question 6.

**Mathematical PRACTICE 4 Model Math** Suki’s watercolor set has 3 rows of paint. There are 8 colors in each row. Write a multiplication sentence to find the total number of colors in the set.

Answer:

Explanation:

Suki’s watercolor set has 3 rows of paint

There are 8 colors in each row

I drew an array with 3 rows and 8 columns

The multiplication sentence that solve the problem is 3 x 8 =

3 x 8 = 24

So, Suki’s watercolor has 24 colors in the set.

Question 7.

A checkerboard has 8 rows, with 8 squares in each row. Write a multiplication sentence to find the total number of squares.

Answer:

Explanation:

A checkerboard has 8 rows, with 8 squares in each row

I drew an array with 8 rows and 8 columns

The multiplication sentence that sole the problem is 8 x 8 =

8 x 8 = 64

So, the total number of squares in the checkerboard has 64 squares.