public static void Main()
Console.WriteLine("zadej cislo");
number1text = Console.ReadLine();
bool isNumber1 = double.TryParse(number1text, out numbers);
Console.WriteLine("zadej druhe cislo");
number2text = Console.ReadLine();
bool isNumber2= double.TryParse(number2text, out numbers);
isNumber = isNumber1 && isNumber2;
Console.WriteLine("Spatny format, zadej cisla znovu");
double number1 = double.Parse(number1text);
double number2 = double.Parse(number2text);
Console.WriteLine("zadej matematickou operaci (+, - , *, / ) ");
string operationText = Console.ReadLine();
if (operationText == "+" || operationText == "plus")
result = number1 + number2;
else if (operationText == "-" || operationText == "mínus")
result = number1 - number2;
else if (operationText == "*" || operationText == "krát")
result = number1 * number2;
else if (operationText == "/" || operationText == "dělěno")
result = number1 / number2;
Console.WriteLine("Výsledek je " + result);