SUM addend1 addend2 (SUM addend1 addend2 ...) addend1 + addend2
addend1
addend2
...
Outputs the sum of its inputs. If no inputs are given, then SUM outputs 0.
SHOW 2 + 3 5
SHOW 2 + 3
SHOW (SUM 1 2 3) 6
SHOW (SUM 1 2 3)