Airthmetic confusion...

[Meino Christian Cramer <Meino.Cramer@xxxxxx>]

Hi,

 I got a little confused here:

   (( a = 1 + 2 ))

 works fine, but 
  

   (( b = 1 )) ; (( a = 1 - b ))

 does not  but

   (( a = 1 + b )) 

 does. Seems I cannot asign "0" to a variable.

 But how can it be possible to assure, that no calculation in 
 a script will never result in zero ?

 Keep zshing!
 Meino