Pure mathematics is the world's best game. It is more absorbing than chess, more of a gamble than poker, and lasts longer than Monopoly. It's free. It can be played anywhere - Archimedes did it in a bathtub.

Calculus is the most powerful weapon of thought yet devised by the wit of man.

M4Math helped me a lot.

Thanks m4 maths for helping to get placed in several companies.
I must recommend this website for placement preparations.