16th Mexican Mathematical Olympiad Problems 2002

16th Mexican Mathematical Olympiad Problems 2002A1.  The numbers 1 to 1024 are written one per square on a 32 x 32 board, so that the first row is 1, 2, ... , 32, the second row is 33, 34, ... , 64 and so on. Then the board is divided into four 16 x 16 boards and the position of these boards is moved round clockwise, so that AB goes to DADC CBthen each of the 16 x 16