Private Sub Command1_Click()
     Dim expr As String, code As String, result As String
     ' Ask for an expression, exit if Cancel was pressed
     expr = InputBox$("Enter your expression", "Cheap Calculator")
     If expr = "" Then Exit Sub
 
     ' Prepare the code to be passed to the Script Control,
     ' starting with the definition of the PI constant
     code = "Const PI = 3.14159265358979" & vbCrLf _
         & "Function EvalExpr" & vbCrLf _
         & "  EvalExpr = " & expr & vbCrLf _
         & "End Function"
 
     ' Start with a "clean" control each time 
     ' (if you omit this statement, you get an error the 2nd time
     ' you run this routine, because it would be an attempt to
     ' redefine the PI constant and the EvalExpr function
     ScriptControl1.Reset
     ' Add the code to the Script Control
     ScriptControl1.AddCode code
 
     ' Run the EvalExpr script function to evaluate the expression
     result = ScriptControl1.Run("EvalExpr")
     ' Show the result
     MsgBox expr & " = " & result, vbInformation, "Cheap Calculator"
 End Sub