All the solutions provided in **McGraw Hill My Math Grade 5 Answer Key PDF Chapter 5 Lesson 3 Problem-Solving Investigation: Estimate or Exact Answer** will give you a clear idea of the concepts.

## McGraw-Hill My Math Grade 5 Answer Key Chapter 5 Lesson 3 Problem-Solving Investigation: Estimate or Exact Answer

**Learn the Strategy**

Mrs. Trainer needs to purchase a classroom response clicker and a new calculator. A clicker costs $31.99 and a calculator costs $11.75. About how much money will it cost to buy both?

1. Understand

What facts do you know?

Mrs. Trainer needs to buy a clicker for $31.99 and a calculator for $11.75.

What do you need to find?

about how much it will ____________ to buy the clicker and calculator

Answer:

about how much it will cost to buy the clicker and calculator.

2. Plan

You can _____________ the cost of the clicker and calculator.

Answer:

You can estimate the cost of the clicker and calculator.

3. Solve

Round the costs of the clicker and calculator to the nearest whole dollar.

$31.99 → ___________ $11.75 → ___________

Next, add to find the estimated total cost.

___________ + ____________ = ____________

So, Mrs. Trainer will need to spend about ______________ for the two items.

Answer:

$31.99 → $ 32 $11.75 → $12

Next, add to find the estimated total cost.

$32 + $12 = $44

So, Mrs. Trainer will need to spend about $44 for the two items.

4. Check

Is my answer reasonable? Explain.

Estimate another way. $30 + $10 = _______________

______________ ≈ ________________

Answer:

yes, the answer is reasonable.

$40, $44 ≈ $40

Explanation:

A clicker costs $31.99

a calculator costs $11.75.

Total $ 43.74

Estimate another way.

$30 + $10 = $40

**Practice the Strategy**

Madison drove to her grandparents’ house. They drove 58.6 miles in the first hour, 67.2 miles in the second hour, and 60.5 miles in the third hour. They followed the same route to return home. About how far did Madison’s family travel?

1. Understand

What facts do you know?

The family drove 58.6 miles, 67.2 miles, and 60.5 miles.

What do you need to find?

The approximate distance Madison’s family traveled.

2. Plan

Estimate the number of miles traveled each hour. Add and then double the amount for the return.

3. Solve

For hour one 58.6 miles – 60

For hour Two 67.2 miles – 70

For hour Three 60.5 miles – 60

Total distance travelled = 60 + 70 + 60 = 190

Madison’s family traveled about 190 + 190 = 380 miles.

4. Check

Is my answer reasonable? Explain.

Answer:

The Madison family drove about 60 miles each hour for about 6 hours.

We know 6 × 60 = 360, therefore my answer is reasonable.

**Apply the Strategy**

**Determine whether you need an estimate or an exact answer to solve each problem. Then solve.**

Question 1.

A restaurant can make 95 dinners each night. The restaurant has been sold out for 7 nights in a row. How many dinners were sold during this week?

Answer:

665 dinners were sold.

Explanation:

Given,

A restaurant can make 95 dinners each night.

The restaurant has been sold out for 7 nights in a row

95 × 7 = 665 dinners were sold.

Question 2.

Mathematical PRACTICE Plan Your Solution A gardener has 35 feet of fencing to enclose the garden shown. About how much fencing will be left over after the garden is enclosed?

Answer:

4.7 feet will be left over after the garden is enclosed.

Explanation:

Given,

A gardener has 35 feet f fencing to enclose the garden shown.

The garden feet given are 5.2 + 4.8 + 8.4 + 7.6 + 4.3 = 30.3

We have to find out how much will be left over

35 – 30.3 = 4.7 feet.

Question 3.

A family is renting a cabin for $59.95 a day for 3 days. About how much will they pay for the cabin?

Answer:

$180.

Explanation:

Given,

A family rented a cabin = $59.95 = $60

$60 × 3 = $180

Question 4.

Four friends ordered two pizzas. The cost of each pizza is $13.80. About how much will it cost for both pizzas?

Answer:

$27.60

Explanation:

The cost of each pizza is $13.80.

There are two pizzas.

The cost for both pizzas = is $13.80 × 2 = $27.60

Question 5.

Ann bought two shirts for $28.95 each and a skirt for $33.95. The sales tax was $3.71. About how much did she pay altogether?

Answer:

$66.61

Explanation:

Given,

Ann bought two shirts for $28.95.

A skirt for $33.95.

The sales tax was $3.71.

Total = $28.95 + $33.95 + $3.71

= $66.61

**Review the Strategies**

Use any strategy to solve each problem.

- Determine an estimate or exact answer.
- Make a table.
- Solve a simpler problem.
- Determine extra or missing information.

Question 6.

**Mathematical PRACTICE** if Make Sense of Problems Students at a high school filled out a survey. The results showed that out of 640 students, 331 speak more than one language. How many students speak only one language?

Answer:

309 students.

Explanation:

No of students = 640

No studen whots speak more than one language = 331

640 – 331 = 309 students.

Question 7.

Pablo is dividing a dish of brownies for a party. The brownie mix costs $2.89. He cuts the brownies into squares that measure 3 inches by 3 inches. If the pan is 18 inches long and 12 inches wide, how many brownies did he cut?

Answer:

24 brownies.

Explanation:

The brownie mix costs $2.89.

Pablo cuts the brownies into squares that measure 3 inches by 3 inches.

If the pan is 18 inches long and 12 inches wide

\(\frac{18}{3}\) × \(\frac{12}{3}\)

6 × 4 = 24 brownies

Question 8.

Evita has 9 quarters, 7 dimes, and 5 nickels. Does she have enough money to buy a box of crayons for $3.25?

Answer:

No, she doesn’t. Evita has only $3.20.

Explanation:

Given,

Evita has 9 quarters, 7 dimes, and 5 nickels.

9 × 25 = 225 cents

7 × 10 = 70 cents

5 × 5 = 25 cents

Total money = 225 + 70 + 25 = 320 cents = $3.20

a box of crayons for $3.25

Question 9.

The fisherman with the longest fish wins a fishing competition. About how much longer is the first-place fish than the third-place fish?

Answer:

10.5 cm

Explanation:

Given,

The fish length is 68.7, 59.8 cm, and 58.2 cm.

The first-place fish = 68.7 cm

The second place fish = 59.8 cm

The third place fish = 58.2 cm

The first-place fish than the third-place fish is 68.7 – 58.2 = 10.5 cm

Question 10.

Tammi is planning to buy a video game system for $310. Each month she doubles the amount she saved the previous month. If she saves $10 the first month, in how many months will Tammi have enough money to buy the video game system?

Answer:

In 5 months Tammi has enough money to buy the video game system.

Explanation:

She saved $10 for the first month

$10 + $20+ $40 + $80 + $160 = $310

Hence Tammi will have enough money in 5 months to buy the video game.

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

**Problem Solving**

**Determine whether you need an estimate or an exact answer to solve each problem. Then solve.**

Question 1.

A library wants to buy a new computer that costs $989.99. So far, the library has collected $311.25 in donations. About how much more money does the library need to buy the computer?

Answer:

$700

Explanation:

Cost of the new computer = $989.99 = $1000

Library collected in donations = $311.25 = $300

$1000 – $300 = $700

The estimated answer is $700.

Question 2.

On Friday, a museum had 185 visitors. On Saturday, there were twice as many visitors as Friday. On Sunday, 50 fewer people visited than Saturday. How many people visited the museum during these three days?

Answer:

875 people.

Explanation:

Given,

The museum had 185 visitors.

Saturday there were twice as many visitors as Friday = 185 × 2 = 370

Sunday 50 fewer people visited than Saturday = 370 – 50 = 320

Total number of people visited the museum during these three days = 185 + 370 + 320 = 875 people.

Question 3.

Tomas orders a meal that costs $7.89. Lisa’s meal costs $9.05. About how much is the combined cost of their meals?

Answer:

The estimated answer is $8 + $9 = $17.

Explanation:

Cost of a meal = $7.89

Cost of Lisa’s meal = $9.05

The combined cost of their meals = $7.89 + $9.05 = $8 + $9 = $17.

Question 4.

**Mathematical PRACTICE** Make Sense of Problems The ski team has a race in 3 hours and it is 120 miles away. The team drives 50 miles each hour. Will they arrive at the race on time?

Answer:

Exact answer. Yes they arrive at the race on time.

Explanation:

Given,

The ski team has a race in 3 hours and and 120 miles away.

They drive 50 miles each hour, then they will have driven 50 3 miles in 3 hours. This is about 150 miles and the competition is 120 miles away so they can easily make it.

Question 5.

At the beginning of last year, there were 368 students at the elementary school. By the beginning of this year, 72 of those students had moved. About how many students started the school year this year?

Answer:

The estimated answer is 300 students.

Explanation:

Given,

There were 368 students at the elementary school.

Estimated as 370 students

No of students moveed = 72 = 70

370 – 70 = 300 students.