Question

How to get a correct answers in number series with in a seconds?

Answer 1

Firstly, Do you think, this is possible??
Well, I will say,

(1) I'll say No, Never!!
(2) Yes, you can do this

I am being very much confusing, just go through the points now, 

(1) Number series problems has various categories, these problems may belong to Aptitude type questions, Arithmetic Progression type questions, Geometric Progression type questions, etc....
(2) You can't solve all these problems by a single type of strategy and approach, obviously you need different approaches and strategies... But wait, first you should have to recognize the problem type, "tough huh??"

So now you got what I am trying to say....

Find the next term in each of the following questions....

Q1: 1, 2, 3, 4, .... 
A1: 5, as it is simply the natural numbers listing
Q2: 1, 4, 9, 16, ...
A2: 25, as it is listing of squares of natural numbers
Q3: 1, 2, 4, 7, 11, ...
A3: 16, now just look the pattern, first term is 1, add 1 to it, you get 2, add 2 to it, you get 4, add 3 to it, you get 7, add 4 to it, you get 11, now simply you have to add 5, so answer is 16

Questions are very simple and most difficult at the same time... just practice harder and harder.....

Answer 2

1. Understand the concept of series.
2. Understand the formulas.
3. Do some examples, using each formula.
4. Use your intelligence and experience of previous problems to quickly identify
     the solution.
5. There is no magic. It comes through practice.