Incapacité d'exécuté ce programme

package Departement;

/**
 *


* @author Jonathan

*/
public class Departement {
     private double a;
       private double b;

public void Enregitrement(double a, double b)
    {

this.a = a;
       this.b =b;
     }
     public double Addition(double a, double b){ 
               double c = a+b;
               return c;
           }

public double Soustration(double a, double b){
      double k = a-b;
       return k;
      }
      public double division (double a, double b){
       float y;
         y =                (float) ((float)a/b);
       return y;
      }
      public double Multiplication(double a, double b){ 
               double d = a*b;
               return d;

}
}