$ pl
Welcome to SWI-Prolog (Multi-threaded, Version 5.6.24)
Copyright (c) 1990-2006 University of Amsterdam.
SWI-Prolog comes with ABSOLUTELY NO WARRANTY. This is free software,
and you are welcome to redistribute it under certain conditions.
Please visit http://www.swi-prolog.org for details.

For help, use ?- help(Topic). or ?- apropos(Word).

?- ['crypto.pro'].
%  gv.pro compiled 0.00 sec, 3,112 bytes
%  combosets.pro compiled 0.01 sec, 7,360 bytes
% crypto.pro compiled 0.01 sec, 21,560 bytes

Yes
?- demo.
Problem: numbers = {5,3,15,6,7} and goal = 3
Solution: (15/ ((5 +3) - (6 +7)))

Yes
?- demo.
Problem: numbers = {9,7,3,0,0} and goal = 2
Solution: ((9 -7) + (0* (3 +0)))

Yes
?- demo.
Problem: numbers = {15,1,6,4,13} and goal = 10
Solution: ((15 +1) - (13* (6 -4)))

Yes
?- demo.
Problem: numbers = {1,8,6,11,11} and goal = 15
Solution: ((6 +11) - (11- (1 +8)))

Yes
?- demo.
Problem: numbers = {4,13,0,8,9} and goal = 3
Solution: ((4 +0) / (9- (13 +8)))

Yes
?- demo.
Problem: numbers = {5,11,15,0,5} and goal = 9
Solution: ((5 -11) - (5/ (15 +0)))

Yes
?- demo.
Problem: numbers = {4,11,7,14,9} and goal = 0
Solution: (9* ((7 -14) - (4 -11)))

Yes
?- demo.
Problem: numbers = {12,9,2,5,4} and goal = 11
Solution: (4+ ((12 +9) / (2 -5)))

Yes
?- demo.
Problem: numbers = {5,4,3,6,1} and goal = 7
Solution: ((3 -6) + (1+ (5 +4)))

Yes
?-