Hi,
Is it possible to perform simple calculations in properties like in the
example below?  If so, please provide pointers.
Thanks,
-jay

** Headline 1
:PROPERTIES:
:CUSTOM_ID: headline_1
:DATE: [2016-07-07 Thu]
:END:

** Headline 2
:PROPERTIES:
:CUSTOM_ID: headline_2
*:DATE: [date from headline 1 + 3 days]*
:END: