Hi guys! I am trying to acquire some experience in Mathematica and goal programming. In the example shown in the attached image I am trying to minimize the deviations in order to obtain the first row matrix value nearest to 10. In this case I should obtain x11=5 , n1=5 and p1 =0 instead of i receive these errors: Part::pspec: Part specification Subscript[x, 1,1] is neither an integer nor a list of integers. >> Part::pspec: Part specification 0.6524678079740285` is neither an integer nor a list of integers. >> NMinimize::bcons: The following constraints are not valid. >> Does someone explain me why I obtain these errors??