In a 3×3 square all integers from 1 to 9 are arranged in some way. First, we counted the arithmetic mean of the numbers in four different 2×2 squares (they all turned out to be integers), and then we calculated the arithmetic mean of the four numbers obt… ift.tt/yajfckz

@MathProblem314 Final Answer According to Your Model •The system is harmonically stable (i.e., averages are integers) if: e \in \{1, 5, 9\} •The final average of the four 2×2 square means is: \boxed{12,\ 15,\ \text{or } 18}