Lots of years ago, I guess I was in first prep or so. I read a story of a smart arabian wazir from a couple of centuries back, who did his king and kingdom some great favor that I can’t remember. But when he was asked what he wants for a reward, he didn’t say money or gold. He asked for a chess board and a reward in grains (wheat or rice…etc), such that one grain in the first square, two in the second, four in the third and so on till the 64th square. The king expected he’d ask for something more valuable, because this sounds too easy to provide. But he missed something, the numbers are low and double up slowly in the early squares, but before you even know you’ll be adding up millions and billions, so by the 64th square you’d have a really large number.
I was intrigued by this story, that I took out a new copybook, the one with the little squares and I started adding it up. At first it was easy and reasonable but it quickly got crazy. And I got lost at how many squares I added up! I went back and added a counter so I can trace my progress and stop at the 64th square. While I was adding up I started noticing something, each sum I reached was less than the grains in the next square by 1. Meaning that the 4th square should contain 8 grains, the sum of the previous 3 squares is 7. Same for bigger numbers, in the square which has 1024 grains, the sum of all the previous grains is 1023.
I don’t really remember the final result but it was a very long number I couldn’t name those millions! The only way to read it is to use Mickey Magazine as a reference. Only ‘3am Dahab’ (Uncle Scrooge) has that much money 😀 It was a good exercise for speedy addition and it’s a reason I loved maths back in school and I was pretty good at it. It also was the reason I got into engineering, but I was wrong, I only ‘thought’ I was good at it! xD