All the solutions provided inÂ **McGraw Hill My Math Grade 4 Answer Key PDF Chapter 13 Lesson 2 Problem-Solving Investigation: Solve a Simpler Problem **will give you a clear idea of the concepts.

## McGraw-Hill My Math Grade 4 Answer Key Chapter 13 Lesson 2 Problem-Solving Investigation: Solve a Simpler Problem

**Learn the Strategy**

It takes Jasmine 2 minutes to ride her bike one block. How long does Âˇt take Jasmine to ride the route shown three times?

1. Understand

What facts do you know?

It takes Jasmine ____________ minutes to ride her bike 1 block.

What do you need to find?

how long it will take to ride the route three times

2. Plan

I will solve a simpler problem to find the answer.

3. Solve

So, it takes Jasmine ____________ minutes to ride three times around.

4. Check

Does your answer make sense? Explain.

Answer: Given that, Jasmine takes 2 minutes to ride her bike one block.

We need to find the ride three times time.

The total number of blocks jasmine rides is,

2 + 2+ 2+ 2+ 4+ 4 = 16.

The time to ride 1 block is 2 minutes.

So, three times the number of blocks is 16 x 3 = 48 blocks.

The time taken to ride three times is, 48 x 2 minutes = 96 minutes.

**Practice the Strategy**

Hayden and his friends want to draw a court on the playground to play Four Square. The sides of each of the small squares are 4 feet. What is the perimeter of the entire court?

1. Understand

What facts do you know?

What do you need to find?

2. Plan

3. Solve

4. Check

Does your answer make sense? Explain.

Answer: Given that, Hayden and his friends drew a four-squared court on the playground.

The side of the small square is 4 ft. So, the side of one side is 8 ft.

Now, we will find the perimeter of the entire court.

The formula for the perimeter of a square is 4 x S.

P = 4 x 8 = 32 ft.

So, the perimeter of the entire court is 32 ft.

**Apply the Strategy**

**Solve each problem by solving a simpler problem.**

Question 1.

Clarissa has four pictures that are each the size of the one shown. What will be the perimeter of the rectangle formed if the four pictures are laid end to end as shown?

Answer: The perimeter of the rectangle formed if the four pictures are laid end to end is, 2(3+5) = 2(8) = 16 inches.

Explanation: Given that, Clarissa has four pictures image.

The image length is 3 inches and the width is 5 inches.

Now, we will find the perimeter of the four pictures image.

The formula for the perimeter of the rectangle is 2(l+W)

Perimeter = 2(3+5) = 2(8)

So, the perimeter of the rectangle formed image is 16 inches.

Question 2.

Mr. and Mrs. Lopez are putting square tiles on the floor in their bathroom. They can fit 6 rows of 4 tiles in the bathroom. How many tiles do they need to buy? If each tile costs $5, what is the total cost?

Answer: The total cost is $120.

Explanation: Given that, Mr. and Mrs. Lopez put a square tile on the floor in their bathroom.

They can fit 6 rows of 4 tiles in the bathroom.

Now, find the total number of tiles.

The tiles are 6 x 4 = 24 tiles.

Each tile cost is $5.

We will find the total cost of the tiles.

The cost of 24 tiles is, 24 x $5 = $120

So, the total cost is $120.

Question 3.

Ling is putting up a wallpaper border on three walls that are each 14 feet long and 12 feet tall. How many feet of wallpaper border will she use if she puts the border only at the top of the wall?

Answer: 42 ft of the wallpaper border.

Explanation: Given that, ling is putting a wallpaper border on three walls.

Each wall has 14 ft long and 12 ft tall.

Ling is not wallpapering the entire wall.

So, we don’t find the area. Just, find the linear length.

The length is 3 x 14 ft = 42ft.

Therefore, the wallpaper border is 42 ft.

Question 4.

**Mathematical PRACTICE** Plan Your Solution Takeisha is placing 72 photographs in an album. She will put the same number of photos on each of the 6 pages. She can put 4 pictures in each row. How many rows will be on each page?

Answer: 3 rows will be on each page.

Explanation: Given that, the total number of pages is 6 and the photographs in the album are 72.

She put 4 photos in each row on 6 pages.

Now, we will find the number of rows on each page.

So, 6(4x) = 72

4x = 72/6

4x = 12

x = 12/4

x = 3.

So, they are 3 rows on each page.

Review the Strategies

Use any strategy to solve each problem.

- Solve a simpler problem.
- Draw a picture.
- Make a table.
- Guess, check, and revise.

Question 5.

**Mathematical PRACTICE** Look for a Pattern What is the perimeter of the eighth figure if this pattern continues?

Answer: The eighth figure perimeter is 32.

Explanation: Given that, the pattern with dimensions of 8 x 8.

The pattern will be square because all the sides are equal.

We will find the perimeter of a square pattern.

The formula for the perimeter of a square is, 4*s

Perimeter = 4 x 8 units =32 units

Question 6.

Marcos is making three tile pictures. He uses 310 green tiles to make each picture. He uses 50 fewer red tiles than green tiles for each picture. How many red and green tiles does he use in all?

Answer: 1710 red and green tiles he used in all.

Explanation: Given that, the green tiles are 320 to make each picture.

First, find the red tiles, 310 – 50 = 260.

Making pictures with 3 tiles is,

Red tiles is 260 x 3 = 780 and the green tiles is 310 * 3 = 930.

So, the total number of tiles is 930 + 780 = 1710 tiles.

Question 7.

A type of bacteria doubles in number every 12 hours. After 2 days, there are 48 bacteria. How many bacteria were there at the beginning of the first day?

Answer: At the beginning of the first day, the bacteria is 3.

Explanation: Given that, every 12 hours, bacteria will be doubled.

After 2 days, the bacteria will be 48.

So, At the end of 1 1/2 days, it will be 24.

At end of 1 day, it will be 12.

At end of 1/2 day, it will be 6.

So, at the start, it will be 3.

Question 8.

Martell had boxes he was stacking. Each was 2 feet high. If he stacks 3 boxes on top of a table that is 3 feet high, what will be the total height of the boxes and the table?

Answer: The total height of the boxes and the table is 9.

Explanation: Given that, Martell has 3 boxes, each was 2 feet high.

We will find the total height of the boxes and the table.

First, find the height of the boxes

3 boxes x 2 ft = 6ft

Now, the table height is 3 ft.

So, the total height of the boxes and the table is, 6 ft + 3 ft = 9 ft.

Question 9.

Mr. Waters is building a rectangular sandbox. He needs to buy enough wood to go around the perimeter of the sandbox. If the length is 6 feet and the width is 5 feet, how many feet of wood does Mr. Waters need to buy?

Answer: Mr. Waters needs to buy 22 feet of wood.

Explanation: Given that, the length is 6ft and the width is 5ft.

We will find the wood feet needed to buy.

So, the formula for the perimeter of a rectangular sandbox is, 2 (l + w)

P= 2(6+5) = 2(11)

P = 22 ft.

Therefore, Mr.waters need to buy 22 ft of wood.

### McGraw Hill My Math Grade 4 Chapter 13 Lesson 2 My Homework Answer Key

**Problem Solving**

**Solve each problem by solving a simpler problem.**

Question 1.

There are two identical figures with all sides of equal length. The combined perimeter of the figures is 80 centimeters. What shape are the figures? What is the length of one side?

Answer: The length of one side is 10 cm.

Explanation: Given that,

We have two figures with all sides are equal in length.

The Perimeter is the length of all the sides of the figure added together.

If each side is 10 cm, then all 4 sides of the square are 40 cm.

The combined figure is 80cm.

Question 2.

Miranda packed 19 glass ornaments into each box. She filled 5 boxes. What is the total number of ornaments in the boxes?

Answer: The total number of ornaments in the boxes is 95.

Explanation: Given that, the packed glass ornaments into each box are 19.

She filled 5 boxes.

Now, we will find the total number of ornaments in the boxes.

The total number of ornaments is 19 x 5 = 95.

So, the total number of ornaments in the boxes is 95.

Question 3.

Carrie is making a bed skirt for her twin beds. One mattress side measures 39 inches, and another measure 75 inches. How many feet of fabric will Carrie need to make skirts for both beds?

Answer: 38 feet of fabric will carrier needed to make skirts for both beds.

Explanation: Given that, Carrie is making a bed skirt for her twin beds.

The beds have the same dimensions.

We need to calculate the perimeter of one of them.

Based on the given measurements the shape is a rectangle.

The formula for the Perimeter of a rectangle is, 2(l+w)

P = 2(75+39) = 228 inches.

Now, multiply by 2 (because we need 2 skirts).

P = 2 x 228 = 456inches.

Convert inches into feet. Then, 456 inches into feet is,

456 (1/12) = 38 ft.

Question 4.

Dalton’s dad rides his bike 1 kilometer north, 1 kilometer west, 1 kilometer south, and 2 kilometers east. How many kilometers will Dalton’s dad ride if he follows this path 9 times?

Answer: The total number of kilometers dalton’s ride is 45 km.

Explanation: Given that, Dalton’s dad rides his bike 1 km north, 1 km west, 1 km south, and 2 km east.

We will find the total kilometers dad ride if he follows this path 9 times.

So, the total kilometers is 1km + 1 km + 1 km + 2 km = 5 km.

If he follows this path 9 times.

Then the total kilometers is 5 km * 9 times = 45 km.

Question 5.

**Mathematical PRACTICE** Make Sense of Problems For each mile that Jason runs, Megan runs \(\frac{1}{4}\) a mile farther. If Jason ran 6 miles, how far did Megan run?

Answer: Megan runs 7.5 miles.

Explanation: Given that, Jason runs 1mile.

Megan runs an extra 1/4 mile as Jason.

So, Megan runs 1mile + 1/4 mile = 1.25miles.

Next, Jason runs 6miles then Megan runs 6 * 1.25 = 7.5 miles.