I've got the following objective function:

minimize sum (trueck[k] - time[k]) for all k (1..n).

I tried to set it up like this:

```
IloLinearNumExpr obj = cplex.linearNumExpr();

for(int k=0; k<grossK.length; k++){
    obj.addTerm(1.0, cplex.sum(trueck[k], cplex.negative(time[k])));
}

cplex.addMinimize(obj);

```

The eclipse error message for the 4th line is: 

"The method addTerm(double, IloNumVar) in the type IloLinearNumExpr is not applicable for the arguments (double, IloNumExpr)"

I guess the method "addTerm" is wrong but I can't find a solution. 
Thanks in advance.