diff --git a/gradebook/src/GradeBook/Book.cs b/gradebook/src/GradeBook/Book.cs
index 45bca2b..ada3f20 100644
--- a/gradebook/src/GradeBook/Book.cs
+++ b/gradebook/src/GradeBook/Book.cs
@@ -16,7 +16,13 @@ namespace GradeBook
 
         public void AddGrade(double grade)
         {
-            this.grades.Add(grade);
+            if (grade <= 100 && grade >= 0)
+            {
+                this.grades.Add(grade);
+            } else
+            {
+                throw new ArgumentException($"Invalid {nameof(grade)}");
+            }
         }
 
         public void AddLetterGrade(char letter)
diff --git a/gradebook/src/GradeBook/Program.cs b/gradebook/src/GradeBook/Program.cs
index 935521e..9d61e82 100644
--- a/gradebook/src/GradeBook/Program.cs
+++ b/gradebook/src/GradeBook/Program.cs
@@ -16,8 +16,7 @@ namespace GradeBook
             var book = new Book("Jason's Grade Book");
             string input;
 
-            bool if_continue = true;
-            while (if_continue)
+            while (true)
             {
                 Console.WriteLine("Give input: ");
                 input = Console.ReadLine();
@@ -27,8 +26,24 @@ namespace GradeBook
                     break;
                 } else
                 {
-                    Console.WriteLine($"Received: {input}");
-                    book.AddGrade(Convert.ToDouble(input));
+                    try
+                    {
+                        Console.WriteLine($"Received: {input}");
+                        book.AddGrade(Convert.ToDouble(input));   
+                    }
+                    catch (ArgumentException ex)
+                    {
+                        Console.WriteLine(ex.Message);
+                    }
+                    catch (FormatException ex)
+                    {
+                        Console.WriteLine(ex.Message);
+                    }
+                    finally
+                    {
+                        // Will always run for all catch scenario
+                        Console.WriteLine("Always Done");
+                    }
                 }
             }