2023 Polish Junior Math Olympiad Round 1 P6
Source:
May 21, 2023
combinatorics
Problem Statement
We call the figure shown in the picture consisting of five unit squares a \emph{plus}, and each rectangle consisting of two such squares a \emph{minus}. Does there exist an odd integer with the property that a square with side length can be dissected into pluses and minuses? Justify your answer.
https://wiki-images.artofproblemsolving.com//6/6a/18-1-6.png