All the solutions provided in **McGraw Hill Math Grade 3 Answer Key PDF Chapter 6 Lesson 8 Multiples of 10** will give you a clear idea of the concepts.

## McGraw-Hill My Math Grade 3 Answer Key Chapter 6 Lesson 8 Multiples of 10

The product of a given number, such as 10, and any other number is a multiple. You can use a basic fact and patterns of zeros to mentally find multiples of 10.

**Math in My World**

Example 1

A new hotel has 3 floors. There are 20 rooms on each floor. What is the total number of rooms in the hotel?

Find 3 × 20. ← 20 is a multiple of 10, since 2 × 10 = 20

One Way Use a basic fact and patterns.

3 × 2 = 6 ← basic fact

3 × 20 = ____ ← 3 × 2 = 6, so 3 × 20 = 60

Another Way Use place value.

Think of 3 × 20 as 3 × 2 tens.

Use base-ten blocks to model 3 equal groups of 2 tens. Draw your model at the right.

**Check for Reasonableness**

Use repeated addition.

20 + ____ + ____ = _____

Properties can be used to multiply a number by a multiple of 10.

Answer:

Given that,

The hotel has 3 floors.

There are 20 rooms on each floor.

3 x 20

20 is a multiple of 10.

3 x 20 = 60.

The another way is

3 x 2 tens = 6 tens

So, 3 x 20 = 60.

Therefore there are 60 rooms in the hotel.

The addition sentence is

20 + 20 + 20 = 60.

Example 2

Ellie is buying 2 bags of beads to add to her bead collection. Each bag has 40 beads. How many beads is Ellie buying?

Find 2 × 40.

2 × 40 = 2 × (4 × 10) write 40 as 4 × 10

= (2 × 4) × 10 Find 2 × 4 first.

= ____ × 10 Multiply

= _____

So, Ellie is buying ___ beads.

Answer:

Given that,

Ellie is buying 2 bags of beads to add to her bead collection.

Each bag has 40 beads.

Then find 2 × 40.

2 × 40 = 2 × (4 × 10) write 40 as 4 × 10

= (2 × 4) × 10 Find 2 × 4 first.

= 8 × 10 Multiply

= 80

So, Ellie is buying 80 beads.

Example 3

Find the unknown in 4 × 50 = .

4 × 50 = 200 4 × 5 tens = 20 tens

↑

Sometimes the basic fact has a zero. Keep that zero, then add the other zero.

Answer:

Given that is 4 x 50.

4 x 50 = 200.

4 x 5 tens = 20 tens.

**Talk Math**

Find the product of 3 × 20 and 2 × 30. What do you notice about the products? Is this an example of the Commutative Property of Multiplication? Explain.

Answer:

The product of 3 x 20 = 60.

The product of 2 x 30 = 60.

Here both the products same and it is not a example of commutative property of multiplication.

**Guided Practice**

**Multiply. Use place value.**

Question 1.

2 × 20 = 2 × ___ tens

= ____ tens

So, 2 × 20 = ____.

Answer:

2 x 20 = 2 x 2 tens.

= 40 tens.

So, 2 x 20 = 40.

Multiplication of 2 with 20 then you get 40.

Question 2.

5 × 60 = 5 × ___ tens

= ____ tens

So, 5 × 60 = ____.

Answer:

5 x 60 = 5 x 6 tens.

= 30 tens

So, 5 x 60 = 300

Multiplication of 5 with 60 then you get 300.

**Independent Practice**

**Multiply. Use a basic fact.**

Question 3.

5 × 5 = ____

So, 5 × 50 = ____

Answer:

5 x 5 = 25

Multiplication of 5 with 5 then you get 25.

So, 5 x 50 = 250.

Multiplication of 5 with 50 then you get 250.

Question 4.

6 × 2 = ____

So, 6 × 20 = ____

Answer:

6 x 2 = 12

Multiplication of 6 with 2 then you get 12.

So, 6 x 20 = 120.

Multiplication of 6 with 20 then you get 120.

Question 5.

5 × 7 = ____

So, 5 × 70 = ____

Answer:

5 x 7 = 35.

Multiplication of 5 with 7 then you get 35.

So, 5 x 70 = 350.

Multiplication of 5 with 70 then you get 350.

**Multiply. Use place value.**

Question 6.

5 × 20 = ____

____ × ___ tens = ___ tens

So, 5 × 20 = ___.

Answer:

5 x 20 = 100.

5 x 2 tens = 10 tens.

So, 5 x 20 = 100.

Multiplication of 5 with 20 then you get 100.

Question 7.

2 × 70 = ____

____ × ___ tens = ___ tens

So, 2 × 70 = ___.

Answer:

2 x 70 = 140.

2 x 7 tens = 14 tens.

So, 2 x 70 = 140.

Multiplication of 2 with 70 then you get 140.

Question 8.

8 × 50 = ____

____ × ___ tens = ___ tens

So, 8 × 50 = ___.

Answer:

8 x 50 = 400.

8 x 5 tens = 40 tens

So, 8 x 50 = 400.

Multiplication of 8 with 50 then you get 400.

Question 9.

2 × 80 = ____

____ × ___ tens = ___ tens

So, 2 × 20 = ___.

Answer:

2 x 80 = 160.

2 x 8 tens = 16 tens.

So, 2 x 80 = 160.

Multiplication of 2 with 80 then you get 160.

**Multiply to find each product. Draw lines to match.**

Answer:

**Algebra Find each unknown.**

Question 13.

2 × = 100

The unknown is ____

Answer:

100 divided by 2 = 50.

100/2 = 50.

2 multiplied 50 = 100.

2 x 50 = 100.

The unknown is 100.

Question 14.

2 × = 60

The unknown is ____

Answer:

60 divided by 2 = 30.

60/2 = 30.

2 multiplied 30 = 60.

The unknown is 60.

Question 15.

6 × 50 =

The unknown is ____

Answer:

6 multiplied by 50 = 300.

6 x 50 = 300

The unknown is 300.

**Problem Solving**

**Write a multiplication sentence with a symbol for the unknown for Exercises 16-17. Then solve.**

Question 16.

**Mathematical PRACTICE 2 Use Algebra** Demont’s card album has 20 pages, and 6 trading cards are on each page. How many cards are there in all?

Answer:

Given that,

Demont’s card album has 20 pages.

There are 6 trading cards are on each page.

The total number of cards in an album is 20 x 6 = 120.

120 is the multiple of 10.

Therefore there are 120 cards in an album.

Question 17.

There are 90 houses with 10 windows each. How many windows are there in all?

Answer:

Given that,

There are 90 houses.

Each house has 10 windows.

The total number of windows are 90 x 10 = 900.

900 is the multiple of 10.

Therefore there are 900 windows in all.

Question 18.

Carlita collected 2 boxes of teddy bears. Each box holds 20 bears. She sells each bear for $2. How much money did she earn?

Answer:

Given that,

Carlita collected 2 boxes of teddy bears.

Each box holds 20 bears.

She sells each bear for $2.

The total number of teddy bears is 2 x 20 = 40 bears.

The money she earn is 40 x $2 = $80.

Therefore the money she earn is $80.

**HOT Problems**

Question 19.

**Mathematical PRACTICE 4 Model Math** Write a multiplication sentence that uses a multiple of 10 and has a product of 120.

Answer:

The multiplication sentence is

10 x 1 = 10

The number that multiples of 10 and has a product of 120 is

10 x 12 = 120.

120 is the product.

Question 20.

**Mathematical PRACTICE 8 Look for a Pattern** Describe the pattern you see when multiplying 5 × 30.

___________________

What is the product of 5 × 30?

___________________

Answer:

Multiplication of 5 with 30 then you get 150.

5 x 30 = 150.

150 is the product.

Question 21.

**? Building on the Essential Question** How do basic facts and patterns help me multiply a number by a multiple of 10?

Answer:

Multiples of 10 are 10, 20, 30 and so on.

The basic facts and patterns helps you to multiply a number by a multiple of 10 is adding the 0 to the tens place.

It is 5 x 10 = 50.

5 x 100 = 500.

### McGraw Hill My Math Grade 3 Chapter 6 Lesson 8 My Homework Answer Key

**Practice**

**Multiply. Use place value.**

Question 1.

2 × 40 =

2 × ___ tens = ___ tens

So, 2 × 40 = ____.

Answer:

2 x 40 = 80.

2 x 4 tens = 8 tens.

So, 2 x 40 = 80.

Multiplication of 2 with 40 then you get 80.

Question 2.

5 × 60 =

5 × ___ tens = ___ tens

So, 5 × 60 = ____.

Answer:

5 x 60 = 300.

5 x 6 tens = 30 tens.

So, 5 x 60 = 300.

multiplication of 5 with 60 then you get 300.

Question 3.

5 × 30 =

5 × ___ tens = ___ tens

So, 5 × 30 = ____.

Answer:

5 x 30 = 150.

5 x 3 tens = 15 tens.

So, 5 x 30 = 150.

Multiplication of 5 with 30 then you get 150.

Question 4.

10 × 20 =

10 × ___ tens = ___ tens

So, 10 × 20 = ____.

Answer:

10 x 20 = 200.

10 = 2 tens = 20 tens.

So, 10 x 20 = 200.

Multiplication of 10 with 20 then you get 200.

**Multiply. Use a basic fact.**

Question 5.

10 × 3 = ___

So, 10 × 30 = ___

Answer:

10 x 3 = 30.

Multiplication of 10 with 3 then you get 30.

So, 10 x 30 = 300.

Multiplication of 10 with 30 then you get 300.

Question 6.

2 × 9 = ___

So, 2 × 90 = ___

Answer:

2 x 9 = 18.

Multiplication of 2 with 9 then you get 18.

So, 2 x 90 = 180.

Multiplication of 2 with 90 then you get 180.

Question 7.

2 × 8 = ___

So, 2 × 80 = ___

Answer:

2 x 8 = 16.

Multiplication of 2 with 8 then you get 16.

So, 2 x 80 = 160.

Multiplication of 2 with 80 then you get 160.

Question 8.

5 × 5 = ___

So, 5 × 50 = ___

Answer:

5 x 5 = 25.

Multiplication of 5 with 5 then you get 25.

So, 5 x 50 = 250.

Multiplication of 5 with 50 then you get 250.

**Problem Solving**

**Write a multiplication sentence to solve.**

Question 9.

Harlan has 5 antique watches. Each watch has a value of $90. How much are Harlan’s watches worth in all?

Answer:

Given that,

Harlan has 5 antique watches.

Each watch has a value of $90.

The total worth of the watches is 5 x $90 = $450.

Therefore The Harlan’s watches worth in all is $450.

Question 10.

**Mathematical PRACTICE 1 Keep Trying** Trey uses 40 nails to put up the frame around each window. There are 5 windows in the bedroom. How many nails will Trey use in the bedroom?

Answer:

Given that,

Trey uses 40 nails to put up the frame around each window.

There are 5 windows in the bedroom.

The number of nails used is 40 x 5 = 200.

Therefore the number of nails the Tray used in the bedroom is 200.

Question 11.

Chloe uses 80 candy wrappers to make a paper necklace. She is making necklaces for herself and 9 friends. How many candy wrappers will Chloe need?

Answer:

Given that,

Chloe uses 80 candy wrappers to make a paper necklace.

She is making for his and her 9 friends.

The total number of Necklaces is 1 + 9 = 10.

Each necklaces has 80 candy wrappers means she uses 10 x 80 = 800.

Therefore she needs 800 candy wrappers.

**Vocabulary Check**

Question 12.

Circle the number sentence that shows 20 is a multiple of 2.

2 × 10 = 20 2 + 10 = 12

2 × 5 = 10 10 ÷ 2 = 5

Answer:

20 is the multiple of 2.

2 x 10 = 20.

**Test Practice**

Question 13.

Which is equal to 52 tens?

A. 52,010

B. 5,210

C. 5,200

D. 520

Answer:

Given that is 52 tens.

52 x 10 = 520

Option D is the correct answer.