public override Element CreateElement(ElementPair elements)
 {
     return new SubtractionElement(elements);
 }
 protected override OperatorElement Clone(ElementPair elements)
 {
     return new AssignmentElement(elements);
 }
 public AssignmentElement(ElementPair elements)
     : base(elements)
 {
 }
 public SubtractionElement(ElementPair elements)
     : base(elements)
 {
 }
 public override Element CreateElement(ElementPair elements)
 {
     return new MultiplicationElement(elements);
 }
 public DivisionElement(ElementPair elements)
     : base(elements)
 {
 }
 protected override OperatorElement Clone(ElementPair elements)
 {
     return new SubtractionElement(elements);
 }
 public override Element CreateElement(ElementPair elements)
 {
     return new DivisionElement(elements);
 }
 protected override OperatorElement Clone(ElementPair elements)
 {
     return new DivisionElement(elements);
 }
 public override Element CreateElement(ElementPair elements)
 {
     return new AdditionElement(elements);
 }
 public AdditionElement(ElementPair elements)
     : base(elements)
 {
 }
 public MultiplicationElement(ElementPair elements)
     : base(elements)
 {
 }
 protected override OperatorElement Clone(ElementPair elements)
 {
     return new MultiplicationElement(elements);
 }
 public override Element CreateElement(ElementPair elements)
 {
     return new AssignmentElement(elements);
 }