From: klee@unibwm.de   
      
   On 07.03.2021 04:19, Tom Del Rosso wrote:   
   > This is curious.   
   >   
   > set x=09   
   > set /a y=x   
   >   
   > results in the answer zero, but it should give the invalid number error.   
      
   Seems the "set /a" routine stops parsing a variable when the next character   
   would make the number incorrect and uses the value till this character.   
      
   set x=42a   
   set /a n=1+x+10   
   echo %n%   
      
   results in 53   
      
      
   > set /a y=%x%   
   > does give the expected error.   
      
   Because here the "set /a" routine sees "set /a y=09"   
   and therefore doesn't parse a variable like above.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)