OK here is another answer :) (11X11)-117 = 4 (22x22)-468 = 16 (33x33)-819 = 270 (117+351=468 so 468+351=819)
OK here is another answer :)
(11X11)-117 = 4
(22x22)-468 = 16
(33x33)-819 = 270 (117+351=468 so 468+351=819)