Send to a Friend

What would be the date for these time periods?
If period of time covered is 2011 03 21 to +3 years from that begin date, what is easiest way to find correct dates from begin date with +3 and +100 days and +3 and +90 days?
I was told that I would count the day I am on as 1 and end day as 1.
I believe June 28 or 29 for 100 and June 18 or 19 for 90 is correct?
Using Fluther
or