Mathematics is not about numbers, equations, computations, or algorithms: it is about understanding.

本当の勇気とは、怖いことを知っていながら、それでも前に進むことだ。

数算练习告诉我们算术运算的原理，而不是单单的记忆和不断演算。

The key to successful investing is to have a clear understanding of the market, the risks involved, a disciplined approach, a long-term perspective, a strong understanding of the fundamentals, and a clear understanding of the risks and rewards.