?- consult('crypto.pro').
%  ../gv.pro compiled 0.01 sec, 2,696 bytes
%  ../combosets.pro compiled 0.00 sec, 7,560 bytes
% crypto.pro compiled 0.02 sec, 21,648 bytes

Yes
?- demo.
Problem:  numbers = {4,0,1,4,4} and goal = 12
Solution: ( ( 1 * ( 4 + 0 ) ) + ( 4 + 4 ) )

Yes
?- demo.
Problem:  numbers = {14,0,2,9,11} and goal = 4
Solution: ( ( 9 + 11 ) - ( 2 + ( 14 + 0 ) ) )

Yes
?- demo.
Problem:  numbers = {9,8,4,15,9} and goal = 9
Solution: ( ( 4 - ( 9 - 8 ) ) + ( 15 - 9 ) )

Yes
?- demo.
Problem:  numbers = {6,8,12,4,14} and goal = 4
Solution: ( ( 14 - ( 12 - ( 6 + 8 ) ) ) / 4 )

Yes
?- demo.
Problem:  numbers = {9,2,6,8,4} and goal = 4
Solution: ( ( ( 6 + ( 9 * 2 ) ) - 8 ) / 4 )

Yes
?- demo.
Problem:  numbers = {10,1,3,15,7} and goal = 4
Solution: ( ( 15 + ( 3 + ( 10 * 1 ) ) ) / 7 )

Yes
?- demo.
Problem:  numbers = {12,14,13,11,15} and goal = 11
Solution: ( ( 11 + 15 ) - ( 13 - ( 12 - 14 ) ) )

Yes
?- demo.
Problem:  numbers = {5,5,4,2,13} and goal = 3
Solution: ( ( 4 + ( 5 + 5 ) ) + ( 2 - 13 ) )

Yes
?- demo.
Problem:  numbers = {13,10,9,8,6} and goal = 0
Solution: ( ( 9 - ( 13 + 10 ) ) + ( 8 + 6 ) )

Yes
?- demo.
Problem:  numbers = {9,10,9,15,8} and goal = 8
Solution: ( 8 + ( 15 * ( 10 * ( 9 - 9 ) ) ) )

Yes
?- halt.