Sorting int in c#

i’m trying to sort int so i can get the last digit from the given combination:
for example user inputs 123 i want to separate 3 so i can do mathematical operations on that int like add 3 to some other number.

            Console.WriteLine("Enter the number combination");
            string numbers = Convert.ToString(Console.ReadLine());

            int last_number = Convert.ToInt32(numbers[numbers.Length - 1]);


but its returning 52 etc. something like that, is there any other way? or am i doing it wrong.
but most of all why is returning numbers around 50 why not a single digit.

In numbers you don’t have an integer, you have a string. When you grab (e.g.) the character ‘3’, you don’t have the number 3, but the character ‘3’. If you investigate the ASCII table, you’ll find the character ‘3’ has the integer value of 51.

There’s a bunch of details / alternate solutions here.