Adds N months to a date represented as number. N can be in range from -10000 to 10000.
|addmonths(42097, 3)||42188||42097 corrensponds to April 4th, 2015|
|addmonths(42097, 0-3)||42007||42097 corrensponds to April 4th, 2015|
Note: keep in mind that EasyMorph doesn't support unary minus in expressions - see Example 2 above.