public static string ToHalfExpressionString(this CalculationModel model, string operation)
 {
     if (operation != String.Empty && operation != "=")
     {
         return(String.Format("{0} {1}", model.FirstOperand, operation));
     }
     else
     {
         return(String.Empty);
     }
 }
        public static string ToFullExpressionString(this CalculationModel model)
        {
            switch (model.Operation)
            {
            case "1/x":
                return(String.Format("1 / {0} =", model.SecondOperand));

            case "√":
                return(String.Format("{0}({1}) =", model.Operation, model.SecondOperand));

            default:
                return(String.Format("{0} {1} {2} =", model.FirstOperand, model.Operation, model.SecondOperand));
            }
        }
 public static string ToHalfExpressionString(this CalculationModel model)
 {
     return(model.ToHalfExpressionString(model.Operation));
 }