Article
Illustrations by David SanAngelo

The Case of the Ruined Recipe

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. 

By Jessica McKenna-Ratjen
From the October/November 2021 Issue

Students will use their knowledge of multiplying and dividing fractions to identify the incorrect measurement in a cookie recipe and solve the case.

Lexile: 570L; 520L

Illustrations by David SanAngelo

It was early Sunday morning at the Craft house. The Craft family was hosting a big family dinner that evening. Mom was out grocery shopping, while Caleb and Tanya planned a surprise.

“It’s sad that Nana can’t come this year,” Tanya said. She grabbed a big mixing bowl from the cabinet.

“I know,” said Caleb. “But she’s having fun in Florida. Besides, it will sort of be like she’s here with us when everyone tastes these!” He waved a notecard in the air. Nana Craft’s famous recipe for honey cookies was written in her flawless handwriting.

“How many should we make?” Tanya asked.

“Hmm,” Caleb pondered. “Well, Mom, Dad, and the two of us will be at dinner. So will Uncle James and Aunt Caroline, Aunt Maria, Aunt Lucy, and Cousin Tara. That makes nine. So let’s make a dozen.”

Tanya read the recipe card. “Oh wow, this makes four dozen!”

It was early Sunday morning. The Craft family was going to have a big family dinner that evening. Mom was out grocery shopping. Caleb and Tanya were planning a surprise.

“It’s sad that Nana can’t come this year,” Tanya said. She grabbed a big mixing bowl from the cabinet.

“I know,” said Caleb. “But she’s having fun in Florida. It will be like she’s here with us when everyone tastes these!” He waved a notecard in the air. Nana Craft had written her famous recipe for honey cookies on it.

“How many should we make?” Tanya asked.

“Hmm,” Caleb thought. “Mom and Dad will be at dinner. The two of us will be there too. So will Uncle James and Aunt Caroline. Aunt Maria, Aunt Lucy, and Cousin Tara will also be there. That means nine people will be at dinner. So let’s make a dozen.”

Tanya read the recipe card. “Wow! This recipe makes four dozen cookies!”

Illustrations by David SanAngelo

Caleb Craft

“No problem,” Caleb grinned. “We can just make one-fourth of the recipe!”

Tanya groaned. “Of course you’d make us do division!”

“Hey, division is fun!” Caleb laughed. “And fraction division can involve more multiplication than you might think. How about we do this: I’ll measure out the ingredients that are whole numbers, like the 2 cups of flour and 4 tablespoons of honey. I’ll multiply them by 1/4.  So you'll have the three fraction ingredients to divide by 4.”

“OK,” Tanya said. She gave a sly smile. “But I get to taste-test the cookies first!”

The Craft siblings got started on writing out a new list of ingredients, with the measurements equal to one-quarter of Nana Craft’s original recipe. In a couple of minutes, Tanya and Caleb both had their new lists done and were ready to measure.

Tanya peeked at Caleb’s list. “One-fourth of an egg? How do we measure that?”

Caleb shrugged. “I’ll just beat one egg in a bowl. Then I’ll measure how many tablespoons it is and use 1/4  of that amount. Dad can use the leftover egg in his breakfast sandwich when he gets up.”

“No problem,” Caleb grinned. “We can just make one-fourth of the recipe!”

Tanya groaned. “Of course you’d make us do division!”

“Division is fun!” Caleb laughed. “Fraction division uses more multiplication than you might think. Let’s do this. I’ll measure out the ingredients that are whole numbers. That includes the 2 cups of flour and 4 tablespoons of honey. I’ll multiply them by 1/4. You can work with the three fraction ingredients. You can divide them by 4.”

“OK,” Tanya said. She gave a sly smile. “But I get to taste the cookies first!”

Tanya and Caleb wrote a new list of ingredients. They made the measurements equal to one-quarter of Nana Craft’s recipe. Then they were ready to measure.

Tanya peeked at Caleb’s list. “One-fourth of an egg? How do we measure that?”

Caleb shrugged. “I’ll just beat one egg in a bowl. Then I’ll measure the amount of egg in tablespoons. I’ll use 1/4 of that amount. Dad can use the leftover egg in his breakfast sandwich.”

Illustrations by David SanAngelo

Tanya shook her head. “Do you ever NOT have the answer, Caleb?”

Soon the big mixing bowl was filled with butter, sugar, egg, vanilla, baking powder, and a scoop of honey. Tanya tossed in 1/8 teaspoon of baking soda and salt. She held the bowl while Caleb beat the ingredients with an electric mixer. 

“Mmm,” Tanya exclaimed. “It smells just like Nana’s already!”

“It does,” Caleb agreed. “Now for the flour!”

Tanya carefully poured Caleb’s 1/4 cup of flour into the bowl. She stirred the mixture into a soft dough.

“OK,” Caleb said. “We’re ready to bake!”

As Tanya and Caleb waited, the kitchen filled with the warm scent of baking cookies. But in a flash, another strong smell came from the oven—burning!

“Oh no!” Tanya cried. 

Caleb slipped on oven mitts and pulled the tray out of the oven. All of the cookies were charred. They were also completely flat!

“What happened?” Tanya wailed. “Nana’s cookies never came out like that! Was the recipe wrong?”

Tanya shook her head. “Do you ever NOT have the answer, Caleb?”

Soon the big mixing bowl was filled. It held butter, sugar, egg, vanilla, baking powder, and a scoop of honey. Tanya tossed in 1/8 teaspoon of baking soda and salt. She held the bowl. Caleb beat the ingredients with an electric mixer.

“Mmm,” Tanya exclaimed. “It smells just like Nana’s already!”

“It does,” Caleb agreed. “Now add the flour!”

Tanya lifted Caleb’s 1/4 cup of flour. She carefully poured the flour into the bowl. She stirred the mixture into a soft dough.

“OK,” Caleb said. “We’re ready to bake!”

Tanya and Caleb waited. The kitchen filled with the warm scent of baking cookies. But then another smell came from the oven. Something was burning!

“Oh no!” Tanya cried.

Caleb slipped on oven mitts. He pulled the tray out of the oven. All of the cookies were burned. The cookies were also flat!

“What happened?” Tanya asked. “Nana’s cookies never came out like that! Was the recipe wrong?”

Illustrations by David SanAngelo

“No,” Caleb replied. He lifted the notecard with the recipe Nana had given them. “This is definitely how she makes it. We must have made a mistake in measuring. Tanya, give me your list, and I’ll compare both of ours against Nana’s.”

Tanya bit her lip while Caleb looked over the measurements. “Hurry, Caleb,” she warned. “We might not have time to make another batch to surprise Mom and Dad!”

“Aha,” Caleb exclaimed. He smacked his forehead and chuckled. “Of course! Just goes to show that even math detectives make mistakes!”

“You figured out what went wrong?” Tanya asked, excited.

“I sure did. Let’s try again.”

This time, the smells from the oven were nothing but sweet. Caleb grinned as he pulled out the second tray. “Perfect! They even crinkled on the top just like Nana’s do.”

“Hooray!” Tanya cheered. “And you remember what you promised?”

Caleb laughed. “Of course. Once they’re cooled, the first bite is yours.”

“No,” Caleb replied. He lifted the notecard. He read the recipe again. “This is definitely how she makes it. We must have made a mistake in measuring. Tanya, give me your list. I’ll compare both of our measurements against Nana’s.”

Tanya bit her lip. Caleb looked over the measurements. “Hurry, Caleb,” Tanya warned. “We might not have time to make another batch. Then we won’t be able to surprise Mom and Dad!”

“Aha,” Caleb said. He smacked his forehead. He chuckled. “Of course! Even math detectives make mistakes!”

“You figured out what went wrong?” Tanya asked.

“I sure did. Let’s try again.”

The smells from the oven were only sweet this time. Caleb grinned. He pulled out the second tray. “Perfect! They even crinkled on the top just like Nana’s do.”

“Hooray!” Tanya cheered. “And you remember what you promised?”

Caleb laughed. “Of course. Wait for them to cool. Then you can have the first bite.”

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