Mental calculus training books
- How to Calculate Quickly: Full Course in Speed Arithmetic by Henry Sticker (link to Amazon). It's a full course in speed arithmetic, all packed into one small book.
- Secrets of Mental Math
- Short-Cut Math 150 tricks for quick calculations.
Something a bit more fancy is provided by a company called Art of speed math which also provides a book and training for this.
Other educational/reference books
As you're going to be a trader, it's a good idea to at least read up on the theory of futures and options. It's often not required for a traineeship, but experience learns that knowing this in advance helps a lot.
- Hull's classic Options, Futures & Other Derivatives
- Option Volatility & Pricing by Natenburg. It's somewhat like Hull, but cheaper.
- The Black Swan and/or Fooled by Randomness, by Nassim Nicholas Taleb about the impact of the improbable.
Stories based upon trading
Alternatively, there are a few pockets about trading you might enjoy reading; stories about the rise and fall of companies and some of the larger trading scandals.
- Inventing Money: The Story of Long-Term Capital Management and the Legends Behind It, the story behind LTCM
- When Genius Failed: The Rise and Fall of Long-Term Capital Management, another story about LTCM
- Rogue Trader, the story about (and written by) Nick Leeson who collapsed Barings Bank
- Too Big to Fail
- The Big Short
- Liar's Poker inside Salomon Brothers.