One Grain Of Rice: A Mathematical Folktale
Universal Themes:Cause and Effect, Change, Ingenuity, Magnitude, Patterns, Resourcefulness, Wisdom
Before Reading Questions
- Who here receives an allowance? Are you required to work for that allowance?
- Would you walk my dog each day if I paid you $2.00 a day? Would you do it if I paid you just one penny a day?
- Suppose I paid you one penny on the first day, two pennies on the second day, and four pennies on the third. What pattern develops? Would you work for that pay for one whole month? Let's each make a guess as to what the total number of pennies would be by the month's end.
- Today's tale is set in India. Who can locate India on our map? What can you tell me about India?
Long ago in India, a raja ruled wisely and fairly. Or so he thought. He was wise in that he required much of the rice that was grown to be stored away, in case of famine. He was fair in that he would provide the people of the land with rice, should famine ever strike.
When it does, however, the raja is reluctant to let the rice go (even though it was never his, of course). "Who knows how long the famine will last?" he wonders to himself. "What if there is finally no rice left, not even for the raja himself?"
One day a clever young girl named Rani does a small favor for the raja, who wished to reward her accordingly. He's surprised when she asks for just one grain of rice. Today, that is, and then two the next day, and four the next, and so on for thirty days. The raja agrees, stunned that the girl should not want more.
Over the next thirty days we see the rice being delivered by a colorful procession of animals. We also see the amount of grains delivered each day growing larger and larger, until the author/illustrator is forced to use fold-out pages to show the dozens of elephants required to bring the rice on the last day.
As Demi proves in her chart at the book's close, this simple doubling pattern produces 1,073,741,823 grains of rice (compounded total) by the end of thirty days. If this were pennies, the sum would total $10,737,418.23.
The raja is dumbfounded by the math, and dismayed by his new-found scarcity of rice. Rani informs him that the rice will be used to feed the people, but that she will leave a basket for him if he promises to be "wise and fair" from then on. And he does.
After Reading Questions
- Were our guesses about the total number of pennies for thirty days close to what Rani received?
- At the beginning of the book, the raja believes that he is wise and fair. If that's so, then why wouldn't he share the rice with his people?
- At what point did the raja begin to realize the effects of the doubling?
- Why didn't the author tell us about every single day?
- Compare this book to The King's Chessboard, a similar mathematical tale also set in India. Have students discuss and list the differences. They may also want to compare and contrast the two rulers, and compare and contrast the two beneficiaries, noting their motives in their requests for the odd form of payment.
- The book is full of authentic, specific words such as implored, famine, and plentifully. Discuss with students how context clues helped to define those words. If a word could not be defined through context clues, did that affect the reading of the story?
- Compare this story to other Indian folktales. Are there common characters or themes?
- Rather than offer math ideas, I would like to introduce my readers to Mathwire, an awesome math site which features lesson plans for math-related picture books, as well as free, downloadable related resources for classroom use. For One Grain Of Rice, for example, the site features a lesson plan with pdf handouts, and an interactive website called The Million Dollar Mission.
- On that same Mathwire page you'll discover Two of Everything, a Chinese folktale describing a pot which has magic doubling powers. This book makes another terrific comparison piece for discussion.