One Grain of Rice

[this post written for Saffron Tree]

One Grain of Rice: A Mathematical Folk Tale
by Demi (Charlotte Dumaresq Hunt)

Recommended Age: 8-12 years


This book is clearly not for my 2½ year old. I was looking for conceptual/educational story book for my soon-to-be-8-year-old niece and came across this book by Demi.

Based on an Indian folk tale, this book introduces the mathematical concept of exponential growth. The story is about a clever little girl Rani, who makes a deal with the Raja (King) and eventually humbles him.

Synopsis: A Raja believes he is wise and fair, but, each year, keeps the harvest rice for himself. He refuses to share the rice when a famine hits the village. One fine day, Rani inadvertently manages to help the Raja. The Raja decides to reward Rani for it and says she can ask for anything within reason. So, Rani, the clever little mathematician she is, says: I would like one grain of rice, doubled every day for thirty days: one grain of rice on the first day, two grains of rice on the second day, four grains of rice on the third day and so on for 30 days.

Of course, not being familiar with exponential growth, the Raja thinks this is an acceptable, affordable, trifling sort of reward and agrees. By the end of the 30 days, the power of 2 works its magic and the whole village has enough grains of rice, thoughtfully and generously shared by Rani. The Raja realizes his folly and decides to mend his ways.

Demi's illustrations, inspired by Indian miniature style, are exquisite. The increasing volume of rice each day is depicted beautifully by the variety of animals that deliver the grains of rice each day. First, it is just a few birds with grains of rice in their beaks. Then come the big cats - a leopard, a tiger, and a lion each carrying a small pouch in their mouths. After a fortnight, a goat is pulling a cart that carries a bag of rice and so on... until the enormous procession of elephants in the end to bring the one billion grains of rice after 30 days!

This book combines the mathematical concept with lovely art, not to mention the moral at the end that even a little girl can teach the Raja to be wise.

There are many mathematical exercises based on this book - like how many grains of rice make a cup (or kilogram or pounds) of rice; how many people (approximately, on an average) will one billion grains of rice feed? and so on. The last page of the book has a table which shows the actual numerical progression from one grain of rice to one billion.

At first I was skeptical as I thought it might be too advanced for an 8-year old. But, even if the brilliance of the mathematics doesn't register right away, it is a great starting point for the concept, especially with accompanying practical and fun exercises that can be found on the web, as devised by classroom teachers.

While I have to wait probably a good 4 or 5 years to see how Ana takes to this book, I can readily see my niece being intrigued by this book...

Another concept in mathematics that children might grapple with is that of Factorial and I've heard some good things about Anno's Mysterious Multiplying Jar that I would like to check out next...