anchor.diff:  
   class operator BigRational.Explicit(const Value: BigRational): Integer;
   begin
  -  if FDenom = BigInteger.One then
  +  if Value.FDenom = BigInteger.One then
       Result := Integer(Value.FNum)
     else
       Result := Integer(Value.FNum div Value.FDenom);
  
positive.code: 
  implementation
  
  { BigRational }
  
  class operator BigRational.Add(const Left, Right: BigRational): BigRational;
  
negative.code: 
  class operator BigRational.Explicit(const Value: BigRational): string;
  begin
    Result := Value.ToString;
  end;
  
  class operator BigRational.Explicit(const Value: BigRational): Double;
  