STANDARDS

CCSS: 3.MD.C.7, 3.MD.C.8, 4.MD.A.3, MP1, MP7, MP8

TEKS: 3.6C, 3.7B, 4.5D, 5.4H

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The Case of the Secret Room

Caleb Craft is in fifth grade. He’s a detective. Caleb loves math. He also loves mystery! Can you solve this case with him? Read the story carefully. Then think about the math clues. 

March 2021
By Jessica McKenna-Ratjen

Illustrations by David SanAngelo

“Now let’s go outside to check out my backyard!” Imani shouted.

Imani was giving her friends Caleb and Jo a tour of her family’s new house. She had just moved to town earlier that week. The moving van was still on its way, so the house didn’t have furniture yet. 

Suddenly, thunder boomed. It started pouring rain. 

Jo ran to the window. “Oh no!” he sighed. “What are we going to do now?”

“Let’s go outside and see my backyard!” Imani shouted.

Imani was with her friends Caleb and Jo. She was showing them her family’s new house. She had just moved to town earlier that week. The moving van was still on its way. The house didn’t have furniture yet.

Thunder boomed. It started pouring rain.

Jo ran to the window. “Oh no!” he sighed. “What are we going to do now?”

Illustrations by David SanAngelo

“I guess we could play a board game.” Imani sounded disappointed too. “All my video games are still in the van.”

“Wait!” Jo said. “I’ve got an idea! This was Mr. Ewan’s old house, right? Caleb, do you remember the rumor we heard?”

“You mean that Mr. Ewan had a secret room on the first floor?” Caleb asked.

“Where he hid his treasure!” Jo added.

“Whoa, a secret room!” Imani exclaimed. “Let’s find it!”

Caleb nodded slowly. “Imani, do your parents have any blueprints of the house?” 

“We could play a board game.” Imani sounded sad too. “All my video games are still in the van.”

“Wait!” Jo said. “I’ve got an idea! This was Mr. Ewan’s old house. Caleb, do you remember the rumor we heard?”

“The rumor that Mr. Ewan had a secret room on the first floor?” Caleb asked.

“Where he hid his treasure!” Jo added.

“A secret room!” Imani exclaimed. “Let’s find it!”

Caleb nodded. “Imani, do your parents have any blueprints of the house?”

Illustrations by David SanAngelo

“We do!” Imani ran to the kitchen and came back with a drawing of the first-floor rooms. “It’s a bit smudged,” she said, pointing to several numbers.

 “That’s OK,” Caleb replied. “To find the secret room, we need to measure the walls of the house and compare them with the measurements on this blueprint. If measurements don’t match up, we know something is hidden!”

Jo lifted his foot. “I know! I just measured my shoes for a school project. They’re exactly 8 inches long. We can measure by recording my steps along each wall.”

“Let’s check this one first,” Imani suggested. “This wall is supposed to be 13 feet long.”

Jo placed one foot in front of the other as he walked along the left wall. “A little more than 19 steps,” he said.

“We do!” Imani ran to the kitchen. She came back with a drawing of the rooms on the first floor. “It’s a bit smudged,” she said. She pointed to some of the numbers.

“That’s OK,” Caleb replied. “We need to measure the walls of the house. Then we can compare them with the measurements on this blueprint. We’ll know something is hidden if the measurements don’t match. That’s how we’ll find the secret room!”

Jo lifted his foot. “I just measured my shoes for a school project. They’re exactly 8 inches long. We can use them to measure. I’ll walk along each wall. You can record the number of steps I take.”

“Let’s check this one first,” Imani suggested. “This wall is supposed to be 13 feet long.” Jo walked along the left wall. He placed one foot in front of the other. “A little more than 19 steps,” he said.

“That’s close to 156 inches, or 13 feet. It’s correct!” Caleb said. 

The team continued through the house measuring each wall. Every measurement matched the blueprints. Eventually, they made their way to the kitchen. Imani’s dad walked in. “What are you kids up to?” he asked. 

“We’re searching for a secret room!” answered Imani.

“That’s close to 156 inches. That’s equal to 13 feet. It’s correct!” Caleb said.

The team continued through the house. They measured each wall. Every measurement matched the blueprints. They went to the kitchen. Imani’s dad walked in. “What are you kids up to?” he asked.

“We’re searching for a secret room!” answered Imani.

Illustrations by David SanAngelo

“. . . 10, 11, 12,” Jo counted. He had just finished walking along the kitchen’s left wall. 

“Hmmm,” Caleb said. He leaned over Imani’s blueprints. Then he knocked on the wall between the kitchen and living room. It sounded hollow. 

“Oh wow!” shouted Imani. She pulled on a small dent in the wall. A hidden door opened!

The room was narrow and long. Jars filled with seeds lined the shelves on the walls.

“Well, look at that,” said Imani’s dad. “Mr. Ewan must have been a gardener!”

“Just as I thought!” Caleb grinned. “A secret treasure room that’s exactly 3 feet wide.”

“. . . 10, 11, 12,” Jo counted. He had just finished walking along the kitchen’s left wall.

“Hmmm,” Caleb said. He leaned over Imani’s blueprints. Then he knocked on the wall between the kitchen and living room. It sounded hollow.

“Oh wow!” shouted Imani. She pulled on a small dent in the wall. A hidden door opened!

The room was narrow and long. There were shelves along the walls. Jars were stacked on the shelves. Each jar was filled with seeds.

“Look at that,” said Imani’s dad. “Mr. Ewan must have been a gardener!”

“Just as I thought!” Caleb grinned. “A secret treasure room that’s exactly 3 feet wide.”

MATH TALK

How did Caleb crack the case? What really happened?  

MATH TALK

How did Caleb crack the case? What really happened?  

Area & Perimeter

Hey, detectives! You’ll be one step closer to cracking the case if you try these math problems.

Area & Perimeter

Hey, detectives! You’ll be one step closer to cracking the case if you try these math problems.

4 ft + 7 ft + 4 ft + 7 ft = 

4 ft + 7 ft + 4 ft + 7 ft = 

26 ft − 9 ft = 

26 ft − 9 ft = 

9 ft x 12 ft =

9 ft x 12 ft =

48 in. ÷ 12 in. = 

48 in. ÷ 12 in. = 

Continue the Learning Journey

  • Play the game “Clear the Area” (above) to practice your area skills.
  • Use a measuring tool (like a ruler or measuring tape) to measure different rooms of your home to the nearest foot or inches. Then find the area and perimeter of at least 3 rooms! 
  • What do you like to do when you have to stay inside? Make a list of at least 5 activities you can do when you are indoors. Choose your favorite activity from your list and write a short paragraph explaining why it’s your favorite.

Continue the Learning Journey

  • Play the game “Clear the Area” (above) to practice your area skills.
  • Use a measuring tool (like a ruler or measuring tape) to measure different rooms of your home to the nearest foot or inches. Then find the area and perimeter of at least 3 rooms! 
  • What do you like to do when you have to stay inside? Make a list of at least 5 activities you can do when you are indoors. Choose your favorite activity from your list and write a short paragraph explaining why it’s your favorite.
Geometry
Area, Perimeter
blueprints

Precise drawings of the layout of a house, often done on paper and usually containing measurements
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