Another way...

The number "ab" is really 10a+b, and "ba" is really 10b+a.

So "ab-ba" is really

(10a+b) - (10b + a) = 9(a-b)

The number "c6" is thus a two-digit multiple of nine, ending in 6. So it can only be 36.

Posted By: Partial Angler, Jan 27, 12:14:03