All the solutions provided in **McGraw Hill Math Grade 5 Answer Key PDF Chapter 3 Lesson 5 Estimate Quotients** will give you a clear idea of the concepts.

## McGraw-Hill My Math Grade 5 Answer Key Chapter 3 Lesson 5 Estimate Quotients

**Math in My World**

Example 1

A dog’s heart beats 365 times in 3 minutes. About how many times does a dog’s heart beat in 1 minute?

Estimate 365 ÷ 3.

1. Change 365 to 360 because 365 ÷ 3

360 and 3 are compatible numbers.

2. Divide mentally.

So, a dog’s heart beats about ____ times a minute.

Check Multiply to check your answer.

____ × 3 = ____

You can use both rounding and compatible numbers to help estimate.

Answer:

120 times.

Explanation:

Change 365 to 360, because 365 ÷ 3

360 and 3 are compatible numbers.

Divide mentally.

360 ÷ 3 = 120

So, a dog’s heart beats about 120 times a minute.

Check Multiply to check your answer.

120 × 3 = 360

Example 2

Estimate 208 ÷ 8.

1. Round the dividend to the nearest hundred.

2. Change the divisor to a number that is compatible with the rounded dividend.

3. Divide mentally. ____

So, 208 ÷ 8 is about ____.

Answer:

Explanation:

Estimate 208 ÷ 8.

Round the dividend to the nearest hundred as 200.

Change the divisor to a number that is compatible with the rounded dividend as 10.

Divide mentally. 200 ÷ 10 = 20

So, 208 ÷ 8 is about 20.

**Guided Practice**

Question 1.

Estimate 850 ÷ 9.

Change 850 to 900 because 900 and 9 are compatible numbers.

Divide mentally.

So, 850 ÷ 9 is about _____.

Answer:

Explanation:

Estimate 850 ÷ 9.

Change 850 to 900 because 900 and 9 are compatible numbers.

850 ÷ 9 = 94.4

900 ÷ 9 = 90

Divide mentally.

So, 850 ÷ 9 is about 100.

**Talk Math**

Explain how you could use compatible numbers to estimate 272 ÷ 4.

Answer:

75

Explanation:

Estimate 272 ÷ 4.

Change 272 to 300 because 300 and 4 are compatible numbers.

272 ÷ 4 = 68

300 ÷ 4 = 75

Divide mentally.

So, 272 ÷ 4 is about 75.

**Independent Practice**

**Estimate. Show how you estimated.**

Question 2.

Answer:

Explanation:

Estimate 635 ÷ 8.

Round the dividend to the nearest hundred as 600.

Divide mentally. 600 ÷ 8 = 75

So, 635 ÷ 8 is about 75.

Question 3.

Answer:

Explanation:

Estimate 545 ÷ 5

Round the dividend to the nearest hundred as 500.

Divide mentally. 500 ÷ 5 = 100

So, 545 ÷ 5 is about 100.

Question 4.

Answer:

Explanation:

Estimate 431 ÷ 2.

Round the dividend to the nearest hundred as 400.

Divide mentally. 400 ÷ 2 = 200

So, 431 ÷ 2 is about 200.

Question 5.

374 ÷ 9

_______

Answer:

Explanation:

Estimate 374 ÷ 9.

Round the dividend to the nearest hundred as 400.

Change the divisor to a number that is compatible with the rounded dividend as 10.

Divide mentally. 400 ÷ 10 = 40

So, 374 ÷ 9 is about 40.

Question 6.

395 ÷ 4

_______

Answer:

Explanation:

Estimate 395 ÷ 4

Round the dividend to the nearest hundred as 400.

Divide mentally. 400 ÷ 4 = 100

So, 395 ÷ 4 is about 100.

Question 7.

660 ÷ 7

_______

Answer:

Explanation:

Estimate 660 ÷ 7

Round the dividend to the nearest hundred as 700.

Divide mentally. 700 ÷ 7 = 100

So, 660 ÷ 7 is about 100.

Question 8.

289 ÷ 9

_______

Answer:

Explanation:

Estimate 289 ÷ 9.

Round the dividend to the nearest hundred as 300.

Change the divisor to a number that is compatible with the rounded dividend as 10.

Divide mentally. 300 ÷ 10 = 30

So, 289 ÷ 9 is about 30.

Question 9.

477 ÷ 9

_______

Answer:

Explanation:

Estimate 477 ÷ 9

Round the dividend to the nearest hundred as 500.

Change the divisor to a number that is compatible with the rounded dividend as 10.

Divide mentally. 500 ÷ 10 = 50

So, 477 ÷ 9 is about 50.

Question 10.

230 ÷ 7

_______

Answer:

Explanation:

Estimate 230 ÷ 7

Round the dividend to the nearest hundred as 300.

Change the divisor to a number that is compatible with the rounded dividend as 10.

Divide mentally. 300 ÷ 10 = 30

So, 230 ÷ 7 is about 30.

Question 11.

639 ÷ 7

_______

Answer:

Explanation:

Estimate 639 ÷ 7

Round the dividend to the nearest hundred as 630.

Divide mentally. 630 ÷ 7 = 90

So, 639 ÷ 7 is about 90.

Question 12.

350 ÷ 8

_______

Answer:

Explanation:

Estimate 350 ÷ 8.

Round the dividend to the nearest hundred as 400.

Divide mentally. 400 ÷ 8 = 50

So, 350 ÷ 8 is about 50.

Question 13.

584 ÷ 6

_______

Answer:

Explanation:

Estimate 584 ÷ 6

Round the dividend to the nearest hundred as 600.

Divide mentally. 600 ÷ 6 = 100

So, 584 ÷ 6 is about 100.

**Problem Solving**

Question 14.

**Mathematical PRACTICE 5 Use Math Tools** A grocery store employee puts 8 bagels in each bag. If she has 385 bagels, about how many bags does she need?

Answer:

50 bags.

Explanation:

A grocery store employee puts 8 bagels in each bag.

If she has 385 bagels,

Number of bags she need 385 ÷ 8 = 48.125

Estimate 385 ÷ 8

Round the dividend to the nearest hundred as 400.

Divide mentally. 400 ÷ 8 = 50

So, 385 ÷ 8 is about 50.

Question 15.

A student E-mail to troops contained 250 characters. The 4-line E-mail contained the same number of characters on each line. About how many characters were on each line? Show how you estimated.

Answer:

60 characters.

Explanation:

A student E-mail to troops contained 250 characters.

The 4-line E-mail contained the same number of characters on each line.

Number of characters were on each line,

250 ÷ 4 = 62.5

So, 250 ÷ 4 is about 60.

Question 16.

Jani drives 290 miles in 5 hours. About how many miles does she drive each hour?

Answer:

60 miles.

Explanation:

Jani drives 290 miles in 5 hours.

Number of miles does she drive each hour,

Estimate 290 ÷ 5

Round the dividend to the nearest hundred as 300.

Divide mentally. 300 ÷ 5 = 60

So, 290 ÷ 5 is about 60.

**Hot Problems**

Question 17.

**Mathematical PRACTICE 2 Use Number Sense** Write a division problem. Show two different ways that you can estimate the quotient using compatible numbers.

Answer:

James types 98 words in 7 minutes. About how many words does he type in one minute?

Explanation:

Estimate 98 ÷ 7

Round the dividend to the nearest hundred as 100.

Change the divisor to a number that is compatible with the rounded dividend as 10.

So, 100 and 10 are compatible numbers.

Divide mentally. 100 ÷ 10 = 10

So, 98 ÷ 7 is about 10.

Question 18.

**? Building on the Essential Question** Why is it important to know how to estimate quotients?

Answer:

Estimation is used to compare the estimated quotient with the exact value of the quotient.

We can determine if an answer to a division problem is reasonable or not easily.

Explanation:

To estimate the quotient, we first round off the divisor and the dividend to the nearest tens, hundreds, or thousands and then divide the rounded numbers.

In a division sum, when the divisor is made up of 2 digits or more than 2 digits,

it helps to estimate the quotient and then try to find the actual number.

### McGraw Hill My Math Grade 5 Chapter 3 Lesson 5 My Homework Answer Key

**Practice**

**Estimate. Show how you estimated.**

Question 1.

115 ÷ 2

Answer:

60

Explanation:

Estimate 115 ÷ 2

Round the dividend to the nearest hundred as 120.

Divide mentally. 120 ÷ 2 = 60

So, 115 ÷ 2 is about 60.

Question 2.

791 ÷ 2

Answer:

400

Explanation:

Estimate 791 ÷ 2

Round the dividend to the nearest hundred as 800.

Divide mentally. 800 ÷ 2 = 400

So, 791 ÷ 2 is about 400.

Question 3.

151 ÷ 3

Answer:

50

Explanation:

Estimate 151 ÷ 3

Round the dividend to the nearest hundred as 150.

Divide mentally. 150 ÷ 3 = 50

So, 151 ÷ 3 is about 50.

Question 4.

460 ÷ 9

Answer:

50

Explanation:

Estimate 460 ÷ 9

Round the dividend to the nearest hundred as 500.

Change the divisor to a number that is compatible with the rounded dividend as 10.

Divide mentally. 500 ÷ 10 = 50

So, 460 ÷ 9 is about 50.

Question 5.

477 ÷ 7

Answer:

50

Explanation:

Estimate 477 ÷ 7

Round the dividend to the nearest hundred as 500.

Change the divisor to a number that is compatible with the rounded dividend as 10.

Divide mentally. 500 ÷ 10 = 50

So, 477 ÷ 7 is about 50.

Question 6.

392 ÷ 9

Answer:

40

Explanation:

Estimate 392 ÷ 9

Round the dividend to the nearest hundred as 400.

Change the divisor to a number that is compatible with the rounded dividend as 10.

Divide mentally. 400 ÷ 10 = 40

So, 392 ÷ 9 is about 40.

**Problem Solving**

Question 7.

The table shows how much each fifth grade room earned from a bake sale. The money is going to be given to 6 different charities. If each charity is given an equal amount, about how much will each charity receive? Show how you estimated.

Answer:

$300.

Explanation:

Earnings of 110 room = $327

Earnings of 112 room = $425

Earnings of 114 room = $550

Earnings of 116 room = $486

Total earnings of all rooms = $327 + $425 + $550 + $486 = $1788

So, to get equal amount for each charity we need to divide it by 6.

Estimate $1788 ÷ 6

Round the dividend to the nearest hundred as 1800.

Divide mentally. 1800 ÷ 6 = 300

So, 1788 ÷ 6 is about 300.

Question 8.

There were 317 marbles divided equally among 8 bowls. About how many marbles were in each bowl?

Answer:

40 marbles.

Explanation:

There were 317 marbles divided equally among 8 bowls.

Number of marbles were in each bowl,

Estimate 317 ÷ 8

Round the dividend to the nearest hundred as 320.

Divide mentally. 320 ÷ 8 = 40

So, 317 ÷ 8 is about 40.

Question 9.

**Mathematical PRACTICE 5 Use Math Tools** Emilio has 5 bags of birdseed. Each bag has about 28 ounces of birdseed. If he divides the birdseed equally into 3 containers, about how much birdseed will he put in each container?

Answer:

50 ounce of birdseed.

Explanation:

Emilio has 5 bags of birdseed.

Each bag has about 28 ounces of birdseed.

5 x 28 = 140 ounces.

If he divides the birdseed equally into 3 containers,

about how much birdseed will he put in each container.

Estimate 140 ÷ 3

Round the dividend to the nearest hundred as 150.

Divide mentally. 150 ÷ 3 = 50

So, 140 ÷ 3 is about 50.

**Test Practice**

Question 10.

Which of the following is the most reasonable estimate for the number of Calories in one serving of milk?

A. between 8 and 9

B. less than 80

C. between 80 and 90

D. more than 90

Answer:

Option(C)

Explanation:

Servings of 5 milk contains 430 calories.

The number of Calories in one serving of milk,

430 ÷ 5 = 86 calories.