Add the letters, pair for pair, using the conventional A=1 (etc) and subtract 26 from each and reconvert to the alphabet.
Although this is my methodology I do not dismiss a different approach.
BTW, I wondered about the inclusion of the second set of 'sentences' as a matter of 'devilment', like a "red herring" so to speak!
Mod 26 went through my mind, I think, while devising this. One solver noted that fact. This italics is an add on to what I originally proposed as my solution. |