Private f as String 'your first number
Private s as String 'your second number
private n as String 
private o as String 'this will be your operators variable
Private sum as Double
 
Private Sub MainForm_KeyUp(Byval sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles MyBase.KeyUp
 
Select case e.KeyCode
 Case keys.Numpad0, keys.NumPad1 '(provide all the keycodes)
     f = e.KeyCode.ToString 'this will display what key your pressed
                f = f.Substring(6, 1) 'we will extract the last string of the keycode string
                n = n & f 'we will pass our first number to our variable n
                me.label1.Text = n 'we will display whats on variable n
 
Case keys.Decimal 'hmmm we will make some flavoring here
 n = n & "."
                f = ""
                n = n & f
  Case keys.Add
      o = "+" 'assign a plus sign to operators variable
                s = n 'we will pass our first number to the second number 
                sum= Val(s) + Val(r) '
                me.label1.Text = FormatNumber(sum, 2, TriState.True,  TriState.True, TriState.True)
                n = ""
                r = sum
   Case keys.Subtract
    'do your part, explore, and discover something extraordinary
    'happy coding
 End Select