All the solutions provided in **McGraw Hill My Math Grade 5 Answer Key PDF Chapter 6 Lesson 4 Use Models to Multiply Decimals** will give you a clear idea of the concepts.

## McGraw-Hill My Math Grade 5 Answer Key Chapter 6 Lesson 4 Use Models to Multiply Decimals

**Draw It**

Find 0.3 × 0.7 using a decimal model.

1. Use one 10-by-10 decimal model.

2. Shade a rectangle that is 0.3 unit wide and 0.7 unit long.

3. There are ___________ hundredths in the shaded region. The shaded region represents the area of a rectangle with a length of 0.7 unit and a width of 0.3 unit. So, 0.3 × 0.7 = ___________.

Answer:

0.3 × 0.7 = 0.21

Explanation:

There are 0.21 hundredths in the shaded region.

The shaded region represents the area of a rectangle,

with a length of 0.7 unit and a width of 0.3 unit.

So, 0.3 × 0.7 = 0.21

**Talk About It**

Question 1.

How are the equations 3 × 7 = 21 and 0.3 × 0.7 = 0.21 similar? How are they different?

Answer:

Both are same.

3 × 7 = 21 and 0.3 × 0.7 = 0.21 similar

Explanation:

3 x 7 = 21 is multiplication of whole numbers.

0.3 x 0.7=0.21 is multiplication of decimal numbers.

Question 2.

**Mathematical PRACTICE** Use Math Tools How is using a model to multiply 0.3 by 0.7 similar to finding the area of a rectangle?

Answer:

Mathematical decimal multiplication model and shading of area model by

Using three 10-by-10 decimal models to find the area of rectangle are similar as shown in the above questions.

Explanation:

There are 0.21 hundredths in the shaded region.

The shaded region represents the area of a rectangle,

with a length of 0.7 unit and a width of 0.3 unit.

So, 0.3 × 0.7 = 0.21

**Try It**

Find 0.4 × 2.4 using decimal models.

1. Use three 10-by-10 decimal models side by side.

2. Shade a rectangle that is 0.4 unit wide and ____________ units long.

3. Shade the same amount of squares on a 10-by-10 grid.

4. There are ___________ hundredths in the shaded region.

So, 0.4 × 2.4 = ____________.

Answer:

0.4 × 2.4 = 0.96

Explanation:

Shade a rectangle that is 0.4 unit wide and 2.4 units long.

Shade the same amount of squares on a 10-by-10 grid.

There are 0.96 hundredths in the shaded region.

So, 0.4 × 2.4 = 0.96

**Talk About It**

Question 3.

Without using models, explain why 2 tenths times 3 tenths is equal to 6 hundredths. Use place value in your explanation.

Answer:

0.2 x 0.3 = 0.06

Explanation:

Decimal place value. The first digit after the decimal represents the tenths place.

The next digit after the decimal represents the hundredths place.

0.2 x 0.3 = 0.06

Question 4.

The table shows some factors and their products. Study the table. Write a rule you can use to find the product of two decimals, both to the tenths place, without using models.

Answer:

0.3 x 0.7 = 0.21

\(\frac{3}{10}\) x \(\frac{7}{10}\) = \(\frac{21}{100}\)

Explanation:

When multiplying a number by a decimal less than one,

the product will be smaller than the number being multiplied.

This is because we are finding a fractional amount of a quantity.

0.3 x 0.7 = 0.21

Question 5.

**Mathematical PRACTICE** Stop and Reflect Without using models, find 0.4 × 0.8. Explain how you found the product.

Answer:

0.4 x 0.8 = 0.32

Explanation:

\(\frac{4}{10}\) x \(\frac{8}{10}\) = \(\frac{32}{100}\)

When multiplying a number by a decimal less than one,

the product will be smaller than the number being multiplied.

This is because we are finding a fractional amount of a quantity.

0.4 x 0.8 = 0.32

**Practice It**

**Shade the decimal models to find each product.**

Question 6.

0.4 × 0.8 = ___________

Answer:

0.32

\(\frac{4}{10}\) x \(\frac{8}{10}\) = \(\frac{32}{100}\)

Explanation:

When multiplying a number by a decimal less than one,

the product will be smaller than the number being multiplied.

This is because we are finding a fractional amount of a quantity.

0.4 x 0.8 = 0.32

Question 7.

0.5 × 0.6 = ___________

Answer:

0.3

\(\frac{5}{10}\) x \(\frac{6}{10}\) = \(\frac{30}{100}\)

Explanation:

When multiplying a number by a decimal less than one,

the product will be smaller than the number being multiplied.

This is because we are finding a fractional amount of a quantity.

0.5 x 0.6 = 0.30

Question 8.

0.2 × 0.9 = _____________

Answer:

0.18

\(\frac{2}{10}\) x \(\frac{9}{10}\) = \(\frac{18}{100}\)

Explanation:

When multiplying a number by a decimal less than one,

the product will be smaller than the number being multiplied.

This is because we are finding a fractional amount of a quantity.

0.2 x 0.9 = 0.18

Question 9.

0.4 × 0.6 = ______________

Answer:

0.24

\(\frac{4}{10}\) x \(\frac{6}{10}\) = \(\frac{24}{100}\)

Explanation:

When multiplying a number by a decimal less than one,

the product will be smaller than the number being multiplied.

This is because we are finding a fractional amount of a quantity.

0.4 x 0.6 = 0.24

Question 10.

0.3 × 1.8 = _____________

Answer:

0.54

\(\frac{3}{10}\) x \(\frac{18}{10}\) = \(\frac{54}{100}\)

Explanation:

When multiplying a number by a decimal less than one,

the product will be smaller than the number being multiplied.

This is because we are finding a fractional amount of a quantity.

0.3 x 1.8 = 0.54

Question 11.

0.2 × 1.4 = ______________

Answer:

0.28

\(\frac{2}{10}\) x \(\frac{14}{10}\) = \(\frac{28}{100}\)

Explanation:

When multiplying a number by a decimal less than one,

the product will be smaller than the number being multiplied.

This is because we are finding a fractional amount of a quantity.

0.2 x 1.4 = 0.28

**Apply It**

Question 12.

Diana’s house has a rectangular window on the door with a height of 1.5 feet and a width of 0.8 feet. What is the area of the window? Shade the decimal models to solve the problem.

Answer:

1.2

Explanation:

0.8 x 1.5 = 1.2

\(\frac{8}{10}\) x \(\frac{15}{10}\) = \(\frac{120}{100}\)

Explanation:

When multiplying a number by a decimal less than one, t

he product will be smaller than the number being multiplied.

This is because we are finding a fractional amount of a quantity.

0.8 x 1.5 = 1.2

Question 13.

**Mathematical PRACTICE** Reason Use the decimal model below to explain why 0.5 × 0.11 is 0.055.

Answer:

0.5 x 0.11 = 0.055

\(\frac{5}{10}\) x \(\frac{11}{100}\) = \(\frac{55}{1000}\)

Explanation:

When multiplying a number by a decimal less than one,

the product will be smaller than the number being multiplied.

This is because we are finding a fractional amount of a quantity.

0.5 x 0.11 = 0.055

**Write About It**

Question 14.

How does a model help me multiply decimals?

Answer:

A model is a grid that helps in the multiplication of decimals and whole numbers.

It’s a grid with 10 columns and 10 rows.

It is very easy to solve for the missing factor or product.

### McGraw Hill My Math Grade 5 Chapter 6 Lesson 4 My Homework Answer Key

**Practice**

**Shade the decimal models to find each product.**

Question 1.

0.7 × 0.5 = ____________

Answer:

0.35

Explanation:

When multiplying a number by a decimal less than one,

the product will be smaller than the number being multiplied.

This is because we are finding a fractional amount of a quantity.

0.7 x 0.5 = 0.35

Question 2.

0.8 × 0.2 = _____________

Answer:

0.16

Explanation:

When multiplying a number by a decimal less than one,

the product will be smaller than the number being multiplied.

This is because we are finding a fractional amount of a quantity.

0.8 x 0.2 = 0.16

Question 3.

0.6 × 2.2 = _____________

Answer:

1.32

0.6 × 2.2 = 1.32

Explanation:

When multiplying a number by a decimal more than one,

the product will be larger than the number being multiplied.

This is because we are finding a fractional amount of a quantity.

0.6 x 2.2 = 1.32

**Problem Solving**

**Shade the decimal models to solve each problem.**

Question 4.

Lanny bought 1.4 pounds of rice that cost $0.40 per pound. How much does Lanny pay for the rice?

Answer:

$0.56

0.4 × 1.4 = 0.56

Explanation:

Lanny bought 1.4 pounds of rice that cost $0.40 per pound.

When multiplying a number by a decimal more than one,

the product will be larger than the number being multiplied.

This is because we are finding a fractional amount of a quantity.

Total amount paid by Lanny for rice is,

0.4 x 1.4 = $0.56

Question 5.

Abbey purchased a poster that had a height of 2 feet and a width of 0.7 foot. What is the area of Abbey’s poster?

Answer:

1.4 square feet.

0.7 × 2.0 = 1.4

Explanation:

Abbey purchased a poster that had a height of 2 feet and a width of 0.7 foot.

When multiplying a number by a decimal more than one,

the product will be larger than the number being multiplied.

This is because we are finding a fractional amount of a quantity.

The area of Abbey’s poster is,

0.7 x 2.0 = 1.4 square feet.

Question 6.

**Mathematical PRACTICE** Use Math Tools Diana spends 0.8 hour per day at the pool. If she goes to the pool for 2 days one week, how many total hours does Diana spend at the pool that week?

Answer:

1.6 hours.

0.8 × 2.0 = 1.6

Explanation:

Diana spends 0.8 hour per day at the pool.

If she goes to the pool for 2 days one week,

When multiplying a number by a decimal more than one,

the product will be larger than the number being multiplied.

This is because we are finding a fractional amount of a quantity.

Total hours does Diana spend at the pool that week,

0.8 x 2.0 = 1.6 hours.