“…In the ring Z 48 . Then U (Z 48 ) = {1, 5,7,11,13,17,19,23,25,29,31,35,37,41,43, 47}, N il(Z 48 ) = {0, 6, 12, 18, 24, 30, 36, 42}, Id(Z 48 ) = {0, 1, 16, 33}. By direct calculation, one easily check that Z 48 is a strongly 2-NC ring, with every unit is of order 4.…”