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

All the solutions provided in McGraw Hill Math Grade 5 Answer Key PDF Chapter 3 Lesson 5 Estimate QuotientsÂ 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 Ă· 3.

1. Change 365 to 360 because 365 Ă· 3
360 and 3 are compatible numbers.

2. Divide mentally.
So, a dogâ€™s heart beats about ____ times a minute.
____ Ă— 3 = ____

You can use both rounding and compatible numbers to help estimate.
120 times.
Explanation:
Change 365 to 360, because 365 Ă· 3
360 and 3 are compatible numbers.
Divide mentally.
360 Ă· 3 = 120
So, a dogâ€™s heart beats about 120 times a minute.
120 Ă— 3 = 360

Example 2
Estimate 208 Ă· 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 Ă· 8 is about ____.

Explanation:
Estimate 208 Ă· 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 Ă· 10 = 20
So, 208 Ă· 8 is about 20.

Guided Practice

Question 1.
Estimate 850 Ă· 9.
Change 850 to 900 because 900 and 9 are compatible numbers.

Divide mentally.
So, 850 Ă· 9 is about _____.

Explanation:
Estimate 850 Ă· 9.
Change 850 to 900 because 900 and 9 are compatible numbers.
850 Ă· 9 = 94.4
900 Ă· 9 = 90
Divide mentally.
So, 850 Ă· 9 is about 100.

Talk Math
Explain how you could use compatible numbers to estimate 272 Ă· 4.

75
Explanation:
Estimate 272 Ă· 4.
Change 272 to 300 because 300 and 4 are compatible numbers.
272 Ă· 4 = 68
300 Ă· 4 = 75
Divide mentally.
So, 272 Ă· 4 is about 75.

Independent Practice

Estimate. Show how you estimated.

Question 2.

Explanation:
Estimate 635 Ă· 8.
Round the dividend to the nearest hundred as 600.
Divide mentally. 600 Ă· 8 = 75
So, 635 Ă· 8 is about 75.

Question 3.

Explanation:
Estimate 545 Ă· 5
Round the dividend to the nearest hundred as 500.
Divide mentally. 500 Ă· 5 = 100
So, 545 Ă· 5 is about 100.

Question 4.

Explanation:
Estimate 431 Ă· 2.
Round the dividend to the nearest hundred as 400.
Divide mentally. 400 Ă· 2 = 200
So, 431 Ă· 2 is about 200.

Question 5.
374 Ă· 9
_______

Explanation:
Estimate 374 Ă· 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 Ă· 10 = 40
So, 374 Ă· 9 is about 40.

Question 6.
395 Ă· 4
_______

Explanation:
Estimate 395 Ă· 4
Round the dividend to the nearest hundred as 400.
Divide mentally. 400 Ă· 4 = 100
So, 395 Ă· 4 is about 100.

Question 7.
660 Ă· 7
_______

Explanation:
Estimate 660 Ă· 7
Round the dividend to the nearest hundred as 700.
Divide mentally. 700 Ă· 7 = 100
So, 660 Ă· 7 is about 100.

Question 8.
289 Ă· 9
_______

Explanation:
Estimate 289 Ă· 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 Ă· 10 = 30
So, 289 Ă· 9 is about 30.

Question 9.
477 Ă· 9
_______

Explanation:
Estimate 477 Ă· 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 Ă· 10 = 50
So, 477 Ă· 9 is about 50.

Question 10.
230 Ă· 7
_______

Explanation:
Estimate 230 Ă· 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 Ă· 10 = 30
So, 230 Ă· 7 is about 30.

Question 11.
639 Ă· 7
_______

Explanation:
Estimate 639 Ă· 7
Round the dividend to the nearest hundred as 630.
Divide mentally. 630 Ă· 7 = 90
So, 639 Ă· 7 is about 90.

Question 12.
350 Ă· 8
_______

Explanation:
Estimate 350 Ă· 8.
Round the dividend to the nearest hundred as 400.
Divide mentally. 400 Ă· 8 = 50
So, 350 Ă· 8 is about 50.

Question 13.
584 Ă· 6
_______

Explanation:
Estimate 584 Ă· 6
Round the dividend to the nearest hundred as 600.
Divide mentally. 600 Ă· 6 = 100
So, 584 Ă· 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?

50 bags.
Explanation:
A grocery store employee puts 8 bagels in each bag.
If she has 385 bagels,
Number of bags she need 385 Ă· 8 = 48.125
Estimate 385 Ă· 8
Round the dividend to the nearest hundred as 400.
Divide mentally. 400 Ă· 8 = 50
So, 385 Ă· 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.
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 Ă· 4 = 62.5
So, 250 Ă· 4 is about 60.

Question 16.
Jani drives 290 miles in 5 hours. About how many miles does she drive each hour?
60 miles.
Explanation:
Jani drives 290 miles in 5 hours.
Number of miles does she drive each hour,
Estimate 290 Ă· 5
Round the dividend to the nearest hundred as 300.
Divide mentally. 300 Ă· 5 = 60
So, 290 Ă· 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.
James types 98 words in 7 minutes. About how many words does he type in one minute?
Explanation:
Estimate 98 Ă· 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 Ă· 10 = 10
So, 98 Ă· 7 is about 10.

Question 18.
? Building on the Essential Question Why is it important to know how to estimate quotients?
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 Ă· 2
60
Explanation:
Estimate 115 Ă· 2
Round the dividend to the nearest hundred as 120.
Divide mentally. 120 Ă· 2 = 60
So, 115 Ă· 2 is about 60.

Question 2.
791 Ă· 2
400
Explanation:
Estimate 791 Ă· 2
Round the dividend to the nearest hundred as 800.
Divide mentally. 800 Ă· 2 = 400
So, 791 Ă· 2 is about 400.

Question 3.
151 Ă· 3
50
Explanation:
Estimate 151 Ă· 3
Round the dividend to the nearest hundred as 150.
Divide mentally. 150 Ă· 3 = 50
So, 151 Ă· 3 is about 50.

Question 4.
460 Ă· 9
50
Explanation:
Estimate 460 Ă· 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 Ă· 10 = 50
So, 460 Ă· 9 is about 50.

Question 5.
477 Ă· 7
50
Explanation:
Estimate 477 Ă· 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 Ă· 10 = 50
So, 477 Ă· 7 is about 50.

Question 6.
392 Ă· 9
40
Explanation:
Estimate 392 Ă· 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 Ă· 10 = 40
So, 392 Ă· 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.

$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 Ă· 6
Round the dividend to the nearest hundred as 1800.
Divide mentally. 1800 Ă· 6 = 300
So, 1788 Ă· 6 is about 300.

Question 8.
There were 317 marbles divided equally among 8 bowls. About how many marbles were in each bowl?
40 marbles.
Explanation:
There were 317 marbles divided equally among 8 bowls.
Number of marbles were in each bowl,
Estimate 317 Ă· 8
Round the dividend to the nearest hundred as 320.
Divide mentally. 320 Ă· 8 = 40
So, 317 Ă· 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?
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 Ă· 3
Round the dividend to the nearest hundred as 150.
Divide mentally. 150 Ă· 3 = 50
So, 140 Ă· 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