Peter Arvidsson wrote: > > I am about to do > <dtml-call "REQUEST.set('a', (a - b) * 15"> I presume that should be: <dtml-call "REQUEST.set('a', (a - b) * 15)"> ? ;-) Anyway, two options: 1. On your form, change your input to be: <input type="TEXT" name="a:int"> 2. Change your call to be: <dtml-call "REQUEST.set('a', (_.int(a) - _.int(b)) * 15)"> cheers, Chris