A lot of us have are slow in solving questions even after fine concepts.

That is due to bad calculation speed.

 

Here are some tips, how to go about it:

1) One must be absolutely well done with addition and subtraction of single digit.You may find it funny that I am saying this to people preparing for JEE,but its true and this is wat makes me faster than a lot of my friends.

 

2) Next is for multiplication.

The most useful in this context is the distributive property.

a*(b+c) = a*b + a*c

Looks simple but extremely useful.

For e.g

How about multiplying 9234 by 6?

This can be done orally.

Guess how?

9234 * 6 = 9234 * 5 + 9234

             = (9234/2)* 10 + 9234 * 1

All the above calculations are easy to be done.(Here I assume that you find addition easier than multiplication, which is usually true)