Option Explicit

Private lngDisplay As Long

Private Sub cmdClear_Click()
    ' We want to clear the display and all arrays
    lngDisplay = 0
    lblDisp.Caption = ""
End Sub

Private Sub Form_KeyDown(KeyCode As Integer, Shift As Integer)
    Select Case KeyCode
        Case 48: lblDisp.Caption = lblDisp.Caption & "0"
        Case 49: lblDisp.Caption = lblDisp.Caption & "1"
    End Select
End Sub

Private Sub Form_LostFocus()
    frmCalc.SetFocus
End Sub