VB Help needed

[relpats]

Hello,
I am taking a class and haven't done any programming before. I am trying to edit a calculation program to allow a user to continue in the program when a "system.overflow.exception" occurs without changing my variable type. I have tried using a try/catch and if > neither are working.

The code I am using is as follow:

'Determine checked button and calculate
If RadioButton1.Checked And FirstNum + SecondNum > 32500 = True Then
MsgBox("Number to large and resulted in overflow. Please enter a smaller number.")
Else
TextBox3.Text = FirstNum + SecondNum
End If

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 And SecondNum = 0 Or FirstNum = 0 = True Then
MsgBox("You can't divide by zero! Please enter another number")
Else
TextBox3.Text = FirstNum / SecondNum
End If

I would appreciate any help I can get.