IMO Shortlist 1984 problem 7
Dodao/la: arhiva2. travnja 2012.
(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 forms
is divisible by four.
(b) Solve the analogous problem for
Izvor: Međunarodna matematička olimpijada, shortlist 1984