eleven+two=twelve+one
is an anagram equality
and
1 + 12 = 2 + 11
may be viewed as a palindrome.
After solving two independent alphametics:
(i). two*one=pigeon
and
(ii). twelve-eleven=equal
use your head to assign a digit to the ? in this puzzle's title,
to make 027 028?9
a meaningful expression.