Use this storybook guide with the book “Cao Chong Weighs an Elephant.”
Many public libraries have this book. This book is a Mathical Award winner.
About the Story
In ancient China, the emperor gave young Chong’s father the gift of an enormous elephant, an animal no one in his city had seen before. People wondered how much the elephant weighed. How could they measure its weight? No one knew. But then Chong whispered a clever solution to his father. It involved a boat, measurement scales, and some rocks. The method worked and Chong was applauded for his intelligence and ingenuity.
Words to Learn
weight, mass, balance, enormous, dimensions, combined
ancient, Prime Minister, Wu Kingdom, ambassador, applauded, spectators, jade, jin (a unit of weight), stumps, advisor, honorable, determine, brainstorm, ingenious
About the Math
From reading the story of how Chong weighed the
elephant, your child can learn:
- Sometimes, the most direct approach to solving a problem (using a balance scale to weigh the elephant) doesn’t work.
- Solving a problem often requires creativity and non-conventional thinking.
- Chong’s method involved three steps: determining how much the elephant’s weight made the boat sink in the water, putting enough rocks in the boat (without the elephant in it) to sink the boat to the same level, and weighing the rocks.
- Weighing the rocks was easy. The cleverness was in using the rocks as a substitute for the elephant to determine the animal’s weight.
Math Talk During Reading
- DISCUSS CHONG’S METHOD OF WEIGHING THE ELEPHANT
How did Chong figure out how the elephant’s weight affected the boat? (He made a line showing how far the boat sank.) Why did Chong put rocks in the boat? (To make the boat sink to the same level as when the elephant was in it.)
- THINK ABOUT OTHER APPROACHES
Suppose you don’t have rocks. What could you use instead? (Cans of macaroni or other things!)
- TALK ABOUT CHONG’S THINKING
What did Chong do before he added up the numbers? (He thought about the problem and developed an indirect method that allowed him to calculate. Calculation came last.)
Try to come up with some of your own questions and comments, too!
Activity After Reading
- USE CHONG’S METHOD TO WEIGH SOMETHING AT HOME
Let’s weigh this orange. First, we’ll put it in this plastic container and then we’ll see how much the container sinks in water. After removing the orange from the container, we’ll put pennies in the container. Finally, we’ll weigh the pennies.