Hi guys,
thank you for the support.

I tested all of your suggestion.
the Sayzer solution require 34 bytes,
the 1st Mister_e solution require 83 bytes,
the 2nd solution require 66 bytes.
the Melanie idea for solution:
---------------
array var word [5]
C var byte

for c = 1 to 9 step 2
if array.lowbyte(c) = 0 then gosub Compute
next
end

Compute:
'Do something
return
------------------
require 35 bytes.

The winner is:......... Sayzer.

bye
Roberto