A 3x3 magic square uses the digits 1 through 9 exactly once, such that every row, column, and main diagonal sums to 15. The center square contains 5. If the top-left square contains 1, what number must be in the bottom-right square?
9
The main diagonal passing from top-left to bottom-right must sum to 15. Since top-left is 1 and center is 5, the bottom-right square must be 15 - 1 - 5 = 9.
About this riddle
Logic riddles give you a few facts and ask what must be true. List what you know, cross out what cannot be, and see what is left.
Difficulty: Medium. More like this: Logic riddles with answers or try Einstein's Logic Grid for a different kind of puzzle.
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