using System;

public static class MathGame {

    public static void Main() {

        Random RNDM = new Random();

        int A;

        int B;

        int C;

        for (int i = 0; i == 0; i += 0){

            A = RNDM.Next(0, 10);

            B = RNDM.Next(0, 10);

            C = A + B;

            Console.WriteLine("What is " + A + " + " + B + "?");

            String Answer = Console.ReadLine();

            if (IsNumeric(Answer) && Convert.ToInt16(Answer) == C) {

                Console.WriteLine("Wow good job, you know that " + A + " + " + B  + " = " + C);

            } else {

                Console.WriteLine("Wrong, " + A + " + " + B  + " = " + C);

            }

            Console.WriteLine("");

        }

    }

    public static bool IsNumeric(this string s) {

        foreach (char c in s) {

            if (!char.IsDigit(c) && c != '.') {

                return false;

            }

        }

​

        return true;

    }

}