3. Srinivasa Ramanujan:

Srinivaasa Ramanujan is the renowned Indian Mathematician, without any formal education in pure mathematics. He contributed extraordinarily to mathematical analysis, number theory, infinite series and continued fractions. British Mathematician, G.H. Hardy gave him a credit by calling him as the natural genius. Ramanujan was extremely good at math. The reason, why he developed so much of interest in Math was because when he was just 11 years, his parents gifted him a math textbook on advanced trigonometry from which he decided to learn everything inside that textbook. And when he found that advanced trigonometry very easy, he decided to derive his own sophisticated theorems by himself.