[C#] Methods/ Task - 3 Last Digit In Word

using System;
class LastDigitInWord
{
    static void ReturnWord(int num)
    {
        switch (num)
        {
            case '0':
                Console.WriteLine("zero");
                break;
            case '1':
                Console.WriteLine("one");
                break;
            case '2':
                Console.WriteLine("two");
                break;
            case '3':
                Console.WriteLine("three");
                break;
            case '4':
                Console.WriteLine("four");
                break;
            case '5':
                Console.WriteLine("five");
                break;
            case '6':
                Console.WriteLine("six");
                break;
            case '7':
                Console.WriteLine("seven");
                break;
            case '8':
                Console.WriteLine("eight");
                break;
            case '9':
                Console.WriteLine("nine");
                break;
            default: Console.WriteLine("not a num");
                break;
        }
    }
    static int GetLastNumber(int number)
    {
        string numbers = number.ToString();
        int word = numbers[numbers.Length-1];
        return word;
    }
    static void Main()
    {
        Console.WriteLine("Enter number bigger than 9:");
        int number = int.Parse(Console.ReadLine());

        int stillNumber = GetLastNumber(number);
        ReturnWord(stillNumber);
    }
}