解决数学问题的喜悦是无与伦比的；这是纯粹的智力胜利的时刻。
The joy of solving a mathematical problem is unparalleled; it is a moment of pure intellectual triumph.
译文：人生变化不定，富贵难以预料。
He who refuses to do arithmetic is doomed to talk nonsense.
True leadership in energy means balancing economic growth with environmental responsibility.