Private Sub cmdAddThem_Click()
On Error GoTo hello
    Dim num1 As Double
    Dim num2 As Double
    Dim result As Double
   
    num1 = Val(txtFirstNum.Text)
    num2 = Val(txtSecondNum.Text)
   
    result = num1 + num2
   
    lblOutput.Caption = result
    Exit Sub
hello:
    MsgBox "error: it needs to be a number"
End Sub