9,10 Can integers be written in the cells of a $4 \times 4$ table so that the sum of all the numbers in the table is positive, while the sum of the numbers in each $3 \times 3$ square is negative?
The central square of size $2 \times 2$ is contained in each square of size $3 \times 3$. Place the number -9 in one of the cells of the central square, and fill the rest of the cells in this table with ones. Then the sum of all numbers in the table is $15+(-9)=6$, and the sum of the numbers inside any $3 \times 3$ square is $8+(-9)=-1$.

## Answer

It is possible.