How to "G"uess what nuber someone is thinking.

A little magic trick for today.  I will be able to guess your number, at least within one number.  It will be at the bottom of the post, so no peaking.
First know you are going to be adding up numbers.  There are 4 steps:
Write down the year you were born
Write down the year something special occured in your life
Write down your age
Write down how many years since that special event.



Did you come up with a number?



I bet I know what it is...




IT IS 4020!!!

Hows it done?  Cant tell.  A good magician never tells!