Here is my solution:using System;
public enum ECTSGrade: sbyte // signed byte
{A = 12, B = 10, C = 7, D = 4, E = 2, Fx = 0, F = -3}
public class GradeExercise{
public static void Main(){
ECTSGrade g1 = (ECTSGrade)0,
g2 = ECTSGrade.B;
Console.WriteLine("Grade g1: {0}", g1); // Fx
Console.WriteLine("Grade g2: {0}", g2); // B
Console.WriteLine("Grade g2: {0}", g2+1); // 11 -- not 12
}
}