A few years ago I learned about a really fun and unique way to introduce exponential functions to students: using the book One Grain Of Rice: A Mathematical Folktale by Demi.Set long ago in India, the beautifully illustrated folktale tells the story of a greedy raja (the powerful ruler) who lives lavishly while his people go hungry.
One day, a young girl named Rani returns some of the raja's rice to him after it had fallen out of a basket. The raja offered her anything she wanted as a reward.
"Very well," said Rani. "If it pleases Your Highness, you may reward me in this way. Today, you will give me a single grain of rice. Then, each day for thirty days you will give me double the rice you gave me the day before. Thus, tomorrow you will give me two grains of rice, the next day four grains of rice, and so on for thirty days."The raja, lacking number sense, thinks this is entirely reasonable and agrees. Thirty days later, let's just say a fool and his rice are soon parted.
Here are a few lesson ideas using this book:
- Teach with Picture Books: One Grain of Rice
- A Systems-Based Review - Demi's One Grain of Rice
- Illuminations: One Grain of Rice