>>BTW, number 2 is a little bit unclear. What operation is done on ABCD, and what does empty space between x and 4 mean?
>
>Nadya,
>
>The "x" means to multiply. So it would be ABCD * 4 = DCBA.
>
>Renoir

Yes, I guessed it after I wrote this letter, but was too lazy, to update :) Anyway, I'll think about them in the evening. Too buzy right now...