Faster mental calculations Currently I am preparing for trading exams which tests faster arithmetic skills. For ex- 80 questions (like calculating 0.abc* 0.cd) to be done in 8 minutes. I am trying to memorize the squares and tables and using simple tricks to solve these but still I am able to reach up-to 40 questions. Any suggestions on how to increase my speed for such calculations. Any books or links are appreciated.

Depending on how much time you have to prepare, it is hard to beat Arthur Benjamin's _Secrets of Mental Math_. The Contents in case you are interested and to see whether or not you think it may meet your needs:

1. Mental Addition and Subtraction
2. Basic Multiplication
3. Intermediate Multiplication
4. Mental Division
5. The Art of "Guesstimation"
6. Pencil-and-Paper Math
7. Memorizing Numbers
8. Advanced Multiplication
9. The Art of Mathematical Magic



Manipulation of decimals and the like occurs in chapter 4 on mental division. Personally, I have only worked through the first few chapters, but I was surprised at how effective everything he puts forth is.