Solution to the Problem:
The number five belongs in the square with the question mark.
From the information given in the problem, the two rows containing the shaded boxes must add up to the same
total as the two columns containing the shaded boxes.
Since the shaded boxes are part of both totals, they can be disregarded to create the equation:
14 + 2 + 20 + 10 + 23 + 11 =
25 + 16 + 12 + 13 + 9 + ?
Colin Bowey had a much better solution to the problem.
Click here to see his complete solution