summands_sum([], 0). summands_sum([I|Is], S1) :- sum(I, S2, S1), summands_sum(Is, S2). summands_n_sum(Is,N,S) :- length(Is,N), summands_sum(Is, S). :- summands_n_sum(Is, 6, S). ----- n599 ------------------------Say, we want to specialize this goal.
add pe to the goal.