Answer:
Value 5
Step-by-step explanation:
The number of rows and columns of the Sudoku is not stated; so, I will assume it is 5 by 5, since there is only one gray square left to be occupied.
If 1 - 4 appears in each row and 1 - 4 appears in each column (take for instance, the attached Sudoku image), then the value that should be entered in the gray square is 5.
