Telerik Exam. Enigmanation

namespace _3.Enigmanation
{
    using System;
    using System.Collections.Generic;
    using System.Linq;

    public class Enigmanation
    {
        public static void Main(string[] args)
        {
            checked
            {
                string mathExpression = Console.ReadLine();
                List<double> numsList = new List<double>();
                List<double> bracketNums = new List<double>();
                List<char> operatorsList = new List<char>();
                List<char> bracketOperats = new List<char>();
                int indexLeftBracket = 0;
                double bracketResult = 0;
                for (int i = 0; i < mathExpression.Length; i++)
                {
                    char symb = mathExpression[i];
                    if (symb == '=')
                    {
                        break;
                    }

                    if (char.IsDigit(symb))
                    {
                        numsList.Add(double.Parse(symb.ToString()));
                    }

                    if (symb == '+' || symb == '-' || symb == '*' || symb == '/' || symb == '%')
                    {
                        operatorsList.Add(symb);
                    }

                    if (symb == '(')
                    {
                        indexLeftBracket = i;
                        bracketNums.Clear();
                        bracketOperats.Clear();
                        while (mathExpression[indexLeftBracket] != ')')
                        {
                            symb = mathExpression[indexLeftBracket];
                            if (char.IsDigit(symb))
                            {
                                bracketNums.Add(double.Parse(symb.ToString()));
                            }

                            if (symb == '+' || symb == '-' || symb == '*' || symb == '/' || symb == '%')
                            {
                                bracketOperats.Add(symb);
                            }

                            indexLeftBracket++;
                        }

                        bracketResult = bracketNums[0];
                        for (int j = 0; j < bracketOperats.Count; j++)
                        {
                            bracketResult = CalculateResultFromMathOperator(bracketNums, bracketOperats, bracketResult, j);
                        }

                        numsList.Add(bracketResult);
                        i = indexLeftBracket;
                    }
                }

                double totalResult = numsList[0];
                for (int k = 0; k < operatorsList.Count; k++)
                {
                    totalResult = CalculateResultFromMathOperator(numsList, operatorsList, totalResult, k);
                }

                Console.WriteLine("{0:f3}", totalResult);
            }
        }

        private static double CalculateResultFromMathOperator(List<double> numList, List<char> operatorList, double result, int j)
        {
            checked
            {
                switch (operatorList[j])
                {
                    case '+':
                        result += numList[j + 1];
                        break;
                    case '-':
                        result -= numList[j + 1];
                        break;
                    case '*':
                        result *= numList[j + 1];
                        break;
                    case '/':
                        result /= numList[j + 1];
                        break;
                    case '%':
                        result %= numList[j + 1];
                        break;
                }

                return result;
            }
        }
    }
}