The story goes, a maharaja (a king) was bored and commissioned a lowly mathematician to create a new game for him. The mathematician presented the maharaja with the game of chess. The maharaja was impressed with the game and offered the inventor any reward he wanted. The mathematician requested a single grain of rice. The maharaja said that it was too small of a reward, so the mathematician asked that a single grain of rice be placed on the first square of the chessboard. Then, on the next square two grains of rice, on the third square four grains of rice, with each square having double the amount of the previous square. The maharaja, though still believing it to be a too small reward, agreed.
The maharaja ordered his treasurer to pay the agreed upon sum. A week later, the mathematician returned to ask the maharaja why he had not received his reward. The maharaja, outraged that the treasurer had disobeyed him, summoned the treasurer and demanded to know why the mathematician had not been paid. The treasurer explained that by the time you get even halfway through the chessboard, the amount of grain required was more than the entire kingdom possessed. (By the 41st square on the chessboard, the maharaja would owe more than a trillion grains of rice.) There are also multiple endings to this store as well.
- The maharaja kills the mathematician to avoid paying the reward.
- The mathematician reveals himself to a God and tells the king he does not have to provide the reward. Just remember the lesson.
This is a summary of what my roommate, B, told me when I asked her if there were any Indian stories that she knew. B think she read about it in a bookstore that was a part of the temple her parents went to when she was younger. Most of the books were about Indian stories, but she remembers this in particular because it is pretty famous not just in India, but in the math and finance world. She says it’s a great illustration of exponential, a concept that is hard to visualize/grasp.
B said this was a legend about the day before Holi. This was collected from a message exchange with B since we were both busy with assignments and couldn’t coordinate a time that worked for both of us. I asked her questions and she answered them and then I summarized what she told me to make it into a coherent story.
I think I heard this story somewhere before. I don’t recall if it was the same Indian king, but I remember hearing the concept of the grain of rice expanding exponentially. Maybe it was from some kind of math problem, but just as B said, I think this is a great illustration of the exponential. I think it kind of tells a lesson that you should always think before you answer because the maharaja didn’t think about his options and could have almost starved his entire nation if the treasurer hadn’t caught his mistake.