ADDMONTH()
 Adds or subtracts months to/from a date
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 Syntax

     ADDMONTH([<dDate>], [<nMonth>]) --> dNewDate

 Arguments

     <dDate>  Designates the date to which the <nMonth> months is added.
     The default is the system date.

     <nMonth>  Designates the number of months to add to <dDate>.

 Returns

     ADDMONTH() returns the new date after <nMonth> is added to <dDate>.

 Description

     Use this function to calculate payment due dates based on an invoice
     date and for similar applications.  It permits you to add months to a
     given date.  If you use a negative number, months are subtracted.

 Note

     .  An empty date parameter will result in an empty date.

 Example

     Show today's date, plus 36 months:

     ? "The payment period ends on: ", ADDMONTH(36)