Visual Studio.NET 2003 and Basic Math Application.

I am still learning VB.NET This is problably so simple, that I am not sure what I am missing to solve the codes error messages.
If someone is able to assist, it would be greatly appreciated.

I have a basic math calculator program. This application was designed to perform basic math calculations: +, -, *, /. The program was provided for us and we have to fix the errors in it. I have to keep the varaibles declared as short.


1. Test all operators with the values 8 and 2 to make sure it works as expected.
2. Test the program with 99999 + 99999. This should raise a 'System.OverflowException’ exception.
3. Modify the code to catch and handle the exception so that the user can continue. KEEP the declarations of FirstNum and SecondNum as short.
4. Test the program with ‘9 divide 0’. The result shows ‘infinity’. Actually, the calculation should raise an exception ‘System.DivideByZeroException’. Modify the program so that the user input is validated before the divide operation is performed. For a divide by zero, modify the program to raise an exception, then add the code to handle the exception.
5. Try the test (99 * 999). You should get a 'System.OverflowException’ exception. Fix the problem to handle the exception.
6. Now test the '-' operator using the following test cases: (1) variable1 = 32000 and variable2 = -767 and (2) variable1 = 32000 and variable2 = -768. For the first test case, the result should be 32767. For the second test case, you should get an exception. Explain what is different from the first case and fix the problem to handle the exception.
7. Make sure to create a user-friendly interface to guide the user after the exceptions are handled.


I have stated the code below.

'Declare FirstNum and SecondNum variables as global
    Dim FirstNum, SecondNum As Short

 Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        'Assign text box values to variables
        FirstNum = TextBox1.Text
        SecondNum = TextBox2.Text
        Try
            If RadioButton1.Checked = True Then
                TextBox3.Text = FirstNum + SecondNum
            End If
        Catch Exc As System.OverflowException
            MessageBox.Show("Please choose smaller number")
        End Try
        'Determine checked button and calculate

        If RadioButton2.Checked = True Then
            TextBox3.Text = FirstNum - SecondNum
        End If
        If RadioButton3.Checked = True Then
            TextBox3.Text = FirstNum * SecondNum
        End If
        If RadioButton4.Checked = True Then
            TextBox3.Text = FirstNum / SecondNum
        End If

       
    End Sub

End Class