Numbering fields of chessboard
Source:
September 8, 2010
modular arithmeticcombinatoricsChessboardIMO Shortlist
Problem Statement
(a) Decide whether the fields of the chessboard can be numbered by the numbers in such a way that the sum of the four numbers in each of its parts of one of the formshttp://www.artofproblemsolving.com/Forum/download/file.php?id=28446is divisible by four.(b) Solve the analogous problem forhttp://www.artofproblemsolving.com/Forum/download/file.php?id=28447