Add four to 100, multiply by eight, and then add 62,000. By this rule the circumference of a circle with a diameter of 20,000 can be approached. Thus according to the rule ((4 + 100) × 8 + 62000)/20000 = 62832/20000 = 3.1416, which is accurate to five significant figures.
A personal challenge for me was the fact that, in order to become a great astronomer, I had to spend a lot of time studying at a place in Kusumapura that nobody knows the name of, including me. I'm like 1542 years old. Also dead. Thats another personal challenge.
In my mathematical career, I wrote several texts that took very long and cost me a lot of time that I could have spent figuring out that the Earth is actually a sphere. So I guess that was a personal challenge for me.
“Aryabhatta is the master who, after reaching the furthest shores and plumbing the inmost depths of the sea of ultimate knowledge of mathematics, kinematics and spherics, handed over the three sciences to the learned world”. - my super cool friend, Bhaskara.