public class Steuer {
  public static void main (String[] args) {
    double brutto = 100; /* inkl. USt. */
    double prozentsatz = 20;
    System.out.println (brutto + " brutto");
    double steuer = brutto * prozentsatz / (100.0 + prozentsatz);
    System.out.println (steuer + " USt.");
    double netto = brutto - steuer;
    System.out.println (netto + " netto");
  }
}