func is_numeric a$ .
   h = number a$
   # because every variable must be used
   h = h
   return 1 - error
.
for s$ in [ "abc" "21a" "1234" "-13" "7.65" ]
   if is_numeric s$ = 1
      print s$ & " is numeric"
   else
      print s$ & " is not numeric"
   .
.