From: mokomoji@naver.com   
      
   2021년 3월 7일 일요일 오후 12시 19분 45초 UTC+9에 Tom Del   
   Rosso님이 작성한 내용:   
   > This is curious.    
   >    
   > set x=09    
   > set /a y=x    
   >    
   > results in the answer zero, but it should give the invalid number error.    
   >    
   > set /a y=%x%    
   > does give the expected error.    
   >    
   > BTW I like to use    
   > set /a y=(1%x%-100) ...*/-+...    
   > as a compact way to remove the zero.    
   >    
   > --    
   > Defund the Thought Police   
      
   etc. Zero String strip.   
   Reference document - korean language   
   https://blog.naver.com/mokomoji/222120528528   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)