```
using System;

class Calculator
{
    static void Main(string[] args)
    {
        double num1, num2;
        char operation;

        Console.Write("Enter first number: ");
        num1 = Convert.ToDouble(Console.ReadLine());

        Console.Write("Enter operation: ");
        operation = Convert.ToChar(Console.ReadLine());

        Console.Write("Enter second number: ");
        num2 = Convert.ToDouble(Console.ReadLine());

        switch (operation)
        {
            case '+':
                Console.WriteLine("Answer: " + (num1 + num2));
                break;
            case '-':
                Console.WriteLine("Answer: " + (num1 - num2));
                break;
            case '*':
                Console.WriteLine("Answer: " + (num1 * num2));
                break;
            case '/':
                Console.WriteLine("Answer: " + (num1 / num2));
                break;
            default:
                Console.WriteLine("Invalid operation");
                break;
        }
        Console.ReadLine();
    }
}
```
using System;

class Calculator
{
    static void Main(string[] args)
    {
        double num1, num2;
        char operation;

        Console.Write("Enter first number: ");
        num1 = Convert.ToDouble(Console.ReadLine());

        Console.Write("Enter operation: ");
        operation = Convert.ToChar(Console.ReadLine());

        Console.Write("Enter second number: ");
        num2 = Convert.ToDouble(Console.ReadLine());

        switch (operation)
        {
            case '+':
                Console.WriteLine("Answer: " + (num1 + num2));
                break;
            case '-':
                Console.WriteLine("Answer: " + (num1 - num2));
                break;
            case '*':
                Console.WriteLine("Answer: " + (num1 * num2));
                break;
            case '/':
                Console.WriteLine("Answer: " + (num1 / num2));
                break;
            default:
                Console.WriteLine("Invalid operation");
                break;
        }
        Console.ReadLine();
    }
}