It can Add or Subtract Day from given date, According to digits we enter in Day, week and month.
For Example The calendar day on which a project initiates. It includes the day, month and year.
You Can Enter No of Days which you want to Add or subtract from given Date.
You Can Enter No of weeks which you want to Add or subtract from given Date.For Example It will Add / Subtract by 7 days if u Enter(1 week).
You Can Enter No of Days which you want to date or subtract from given Date.For Example It will Add / Subtract by days in those month if u Enter(1 month).