MathDB
ASU 453 All Soviet Union MO 1987 numbers in 1987x1987 board

Source:

August 7, 2019
combinatoricssquare tabletableSum

Problem Statement

Each field of the 1987×19871987\times 1987 board is filled with numbers, which absolute value is not greater than one. The sum of all the numbers in every 2×22\times 2 square equals 00. Prove that the sum of all the numbers is not greater than 19871987.
Back to ProblemsView on AoPS