math doesn't work in a datamap

I kept getting errors trying to do a simple <= and $var - $var.
the error message was it was expecting a string and wouldn't add them.

when i took the $var out of a datamap and made them unique independent variables the error went away.

wondering if anyone else encountered this issue?


code:
(set: $tick's battrack to $tick's roomtrack) and
(if: (30 <= ($tick's roomtrack - $tick's battrack)) is true)[true]
produces an error about booleans and strings

code:
(set: $roomtrack to 30)(set: $battrack to 0)
(if: (30 <= ($roomtrack - $battrack)) is true)[true]
produces [True]