Cetin,

If you put this code in the interactivechange(), wouldn't you get, for an input of "1234",

1+1+2+1+2+3+1+2+3+4 ?

i.e. the len(trim(this.value) would be 1 then 2 then 3 etc., with each keystyroke. I agree it would be fine in the lostfocus().

Terry

* Textbox1 InteractiveChange or Lostfocus etc
lcValue = ""
for ix=1 to len(trim(this.Value))
 lcValue = lcValue + '+' + substr(this.Value,m.ix,1)
endfor
thisform.textbox2.value = eval(m.lcValue)

PS: It would work for single digits only and no negative values (ie:32 is interpreted as +3+2).
Cetin