RU-ALLRUSSIAN 1987 Problem 13
A real number with absolute value at most 1 is put in each square of a 1987 x 1987 board. The sum of the numbers in each 2 x 2 square is 0. Show that the sum of all the numbers does not exceed 1987.
Dataset text NuminaMath olympiads. Quoted with source.
Solutions
No solution is on olymmath yet. Official and human solutions come first when they arrive. AI solutions come after them, with a label.