We included **HMH Into Math Grade 5 Answer Key PDF** **Module 15 Lesson 5 Multiply Decimals by 2-Digit Whole Numbers **to make students experts in learning maths.

## HMH Into Math Grade 5 Module 15 Lesson 5 Answer Key Multiply Decimals by 2-Digit Whole Numbers

I Can use an area model and place-value patterns to multiply a decimal by a 2-digit whole number.

**Step It Out
**Question 1.

When Sierra gets home from school each day, she drinks a 0.47-liter container of water. Find the amount of water Sierra drinks in 26 days.

A. To solve, find 26 × 0.47. Write each factor in expanded form.

Answer:

Expanded form: 0.47 × 26 = (0.47 × 20) + (0.47 × 6) = 12.22.

Explanation:

Expanded form :

= 0.47 × 26

= 0.47 (20 + 6)

= (0.47 × 20) + (0.47 × 6)

= 9.40 + 2.82

= 12.22 .

B. Use the rectangle to make an area model to represent the problem. Think about how to divide the sections using the expanded form of the factors. Find the partial products by finding the area of each section.

Answer:

Explanation:

The amount of water Sierra drinks in 26 days = Number of container of water Sierra drinks after getting home from school each day × Number of days

= 0.47 liters × 26

= 0.47 (10 + 10) +(3 + 3)

= (0.47 × 10) + (0.47 × 10) + (0.47 × 3) + (0.47 × 3)

= 4.70 + 4.70 + 1.41 + 1.41

= 9.40 + 2.82

= 12.22 liters.

C. Arrange the partial products to find the sum.

Answer:

Explanation:

0.47 × 26 = (20 × 0.4) + (20 × 0.07) + (6 × 0.4) + (6 × 0.07)

= 8 + 1.4 + 2.4 + 0.42

= 9.4 + 2.4 + 0.42

= 11.8 + 0.42

= 12.22.

D. How much water does Sierra drink in 26 days.

Answer:

The amount of water Sierra drinks in 26 days = 12.22 liters.

Explanation:

Number of container of water Sierra drinks after getting home from school each day = 0.47 liters.

Number of days = 26.

The amount of water Sierra drinks in 26 days = Number of container of water Sierra drinks after getting home from school each day × Number of days

= 0.47 liters × 26

= 0.47 (20 + 6)

= (0.47 × 20) + (0.47 × 6)

= 9.40 + 2.82

= 12.22 liters.

**Turn and Talk** Is your answer reasonable? Explain.

Answer:

Yes, its reasonable because the amount of water for 26 days she can be calculated by using multiplication by Number of container of water Sierra drinks after getting home from school each day × Number of days

Explanation:

The amount of water Sierra drinks in 26 days = Number of container of water Sierra drinks after getting home from school each day × Number of days

= 0.47 liters × 26

= 0.47 (20 + 6)

= (0.47 × 20) + (0.47 × 6)

= 9.40 + 2.82

= 12.22 liters.

Question 2.

Kennard rides his bike 3.25 miles each day to get to and from school for the first 34 days of school. How many miles does he ride in those 34 days?

To solve, find 34 × 3.25. Use place-value patterns to find the product using whole numbers.

A. The factor 34 is a whole number. Multiply 3.25 by 100 to make it into a whole number. What is the whole number?

Answer:

The whole number is 325.

Explanation:

3.25 × 100 = 325.

B. Find the product of the whole numbers.

Answer:

The product of the whole numbers: 34 × 100 = 3400.

Explanation:

The whole numbers are 100 and 34:

34 × 100 = 3400.

C. How do you use this product to find the actual product?

Answer:

The product of the whole numbers is used to find the actual product by using division to find the number of days and multiplied by 3.25.

Explanation:

The actual product = 3.25 × 34 = 110.50.

The product of the whole numbers: 34 × 100 = 3400.

(3400 × 3.25) ÷ 100 = 11050 ÷ 100 = 110.50.

D. What is the actual product?

Answer:

The actual product = 3.25 × 34 = 110.50.

Explanation:

The actual product = 3.25 × 34 = 110.50.

E. How many miles does Kennard ride?

Answer:

Number of miles he rides in those 34 days = 110.50.

Explanation:

Number of miles Kennard rides his bike each day to get to and from school = 3.25.

Number of days = 34.

Number of miles he rides in those 34 days = Number of miles Kennard rides his bike each day to get to and from school × Number of days

= 3.25 × 34

= 3.25 (30 + 4)

= (3.25 × 30) + (3.25 × 4)

= 97.5 + 13.00

= 110.50.

F. Is the answer reasonable? Explain.

Answer:

Yes, answer is reasonable because it is performed correctly using multiplication process .

Explanation:

Number of miles he rides in those 34 days = Number of miles Kennard rides his bike each day to get to and from school × Number of days

= 3.25 × 34

= 3.25 (30 + 4)

= (3.25 × 30) + (3.25 × 4)

= 97.5 + 13.00

= 110.50.

**Turn and Talk** Jared rides his bike 2.8 miles each day to get to and from school. Explain how you can use place-value patterns to find 34 × 2.8.

Answer:

Number of miles he rides in those 34 days = 34 × 2.8 = 95.20.

Explanation:

Number of miles Jared rides his bike each day to get to and from school = 2.8.

Place-value patterns to find 34 × 2.8:

34 × 100 = 3400.

(3400 × 2.8) ÷ 100 = 9520 ÷ 100 = 95.20.

**Check Understanding
**Question 1.

The distance around a field is 0.28 mile. If Anya runs around the field 12 times, how many miles does she run? Draw an area model to find the answer.

Answer:

Number of miles she runs = 3.36.

Explanation:

The distance around a field = 0.28 mile.

Number of times Anya runs around the field = 12.

Number of miles she runs = The distance around a field × Number of times Anya runs around the field

= 0.28 × 12

= 3.36.

**On Your Own
**Question 2.

Every minute, 6.8 gallons of water flow from a garden hose into a pool. Find the amount of water in the pool after 32 minutes.

Draw an area model.

Answer:

Number of gallons of water in the pool after 32 minutes = 217.6.

Explanation:

Number of gallons of water flow from a garden hose into a pool every minute = 6.8

Number of minutes gallons of water in the pool after = 32.

Number of gallons of water in the pool after 32 minutes = Number of gallons of water flow from a garden hose into a pool every minute × Number of minutes gallons of water in the pool after

= 6.8 × 32

= 217.6

How much water is in the pool?

Answer:

217.6 number of gallons of water is in the pool.

Explanation:

Number of gallons of water in the pool after 32 minutes = Number of gallons of water flow from a garden hose into a pool every minute × Number of minutes gallons of water in the pool after

= 6.8 × 32

= 217.6

Is your answer reasonable? Explain how you know.

Answer:

Yes, my answer is reasonable because it is calculated correctly and value is correct for the problem.

Explanation:

My answer is reasonable because it is calculated correctly and value is correct for the problem.

Number of gallons of water in the pool after 32 minutes = Number of gallons of water flow from a garden hose into a pool every minute × Number of minutes gallons of water in the pool after

= 6.8 × 32

= 217.6

**Multiply. Show your work.
**Question 3.

Answer:

Explanation:

Multiplication of 2.3 and 14:

2.3 × 14 = 32.2.

Question 4.

Answer:

Explanation:

Multiplication of 0.58 and 23:

0.58 × 23 = 13.34.

Question 5.

Answer:

Explanation:

Multiplication of 24.1 and 82:

24.1 × 82 = 1976.2.

Question 6.

**Critique Reasoning** Antoine multiplies 4.78 by 35 and says the product is 16.73. How do you know that Antoine is incorrect? What is the correct answer?

Answer:

Antoine is incorrect because multiplication of 4.78 by 35 the product is 167.3 not 16.73.

Explanation:

Multiplication of 4.78 by 35:

=> 4.78 × 35 = 167.3.

**Use the table for 7-9.
**The table shows the prices for different items at a used bookstore.

Question 7.

On Monday, the store sells 28 hardback books. How much does the store earn?

Answer:

Amount of money the store earns = $151.20.

Explanation:

Number of hardback books the store sells on Monday = 28.

Cost of each hardback book = $5.40.

Amount of money the store earns = Number of hardback books the store sells on Monday × Cost of each hardback book

= 28 × $5.40

= $151.20.

Question 8.

On Tuesday, the store sells 63 paperback books and 34 magazines. How much does the store earn?

Answer:

Amount of money the store earns = $197.87.

Explanation:

Number of paperback books the store sells on Tuesday = 63.

Cost of each paperback book = $2.79.

Number of magazines the store sells on Tuesday = 34.

Cost of each magazine = $0.65.

Amount of money the store earns = (Number of paperback books the store sells on Tuesday × Cost of each paperback book) + (Number of magazines the store sells on Tuesday × Cost of each magazine)

= (63 × $2.79) + (34 × $0.65)

= $175.77 + $22.1

= $197.87.

Question 9.

On Wednesday, the store sells 52 paperback books and 27 hardback books. Does the store earn more from the paperback books or the hardback books? Explain.

Answer:

Amount of money she earns = $290.88.

The store earn more from the hardback books not from the paperback books.

Explanation:

Number of paperback books the store sells on Wednesday = 52.

Cost of each paperback book = $2.79.

Number of hardback books the store sells on Monday = 27.

Cost of each hardback book = $5.40.

Amount of money she earns = (Number of paperback books the store sells on Wednesday × Cost of each paperback book) + (Number of hardback books the store sells on Monday × Cost of each hardback book)

= (52 × $2.79) + (27 × $5.40)

= $145.08 + $145.80

= $290.88.

Amount of paperback books the store sells on Wednesday = Number of paperback books the store sells on Wednesday × Cost of each paperback book

= 52 × $2.79

= $145.08.

Amount of hardback books the store sells on Wednesday = Number of hardback books the store sells on Wednesday × Cost of each hardback book

= 27 × $5.40

= $145.80.

=> Comparison: $145.08 < $145.80.

Question 10.

**Use Structure** The product 23 × 589 equals 13,547.

Explain how you can use the product to find the value of the expression 23 × 58.9.

Answer:

The value of the expression 23 × 58.9 = 13,54.7.

Explanation:

Product of 23 × 589:

23 × 589 = 13,547.

589 ÷ 10 = 58.9

=> 23 × 589 =13,547 ÷ 10

=> 23 × 58.9 = 13,54.7

Explain how you can use the product to find the value of the expression 23 × 5.89.

Answer:

The value of the expression 23 × 58.9 = 13,54.7.

Explanation:

Product of 23 × 589:

23 × 589 = 13,547.

589 ÷ 10 = 58.9

=> 23 × 589 =13,547 ÷ 10

=> 23 × 58.9 = 13,54.7