A moral and a math tale rolled into one. What more could you ask, except for some delightful illustrations modeled after Indian art and culture? This book is such a pleasure that besides obtaining a copy from myself, I gave one to my mathematics advisor, who thought it was cute as well. It's a clever illustration of the doubling function and a useful teaching tool for the younger grades.
The text is well-written and appropriate for its audience, the pictures are colorful and elegant, and the pull-out poster is just plain fun. What child wouldn't like a scene that simply depicts 256 elephants marching across the page? And the story of a girl who teaches a ruler to be kind and just is classic-not to mention that, being a girl myself, I appreciate the message that is sent by the intelligent main character being female. Finally, the very last page of the book contains a helpful chart that corresponds the grains of rice Rani receives each day to the day she receives it on.
As a side note, parents might find it a fun project to replicate this tale in real life by giving a child a penny and then doubling it for seven days. At the end of the week the child would be the proud owner of $1.27, not to mention possess some newfound math skills. I would advise you to restrict it to a week instead of the thirty days that is used in the book, though. Unless, of course, you've got the $10,737,400 you would be obligated to give lying around the house in spare change. ^_~