Math Puzzle: Fill in the Grid

Distribute the numbers 16, 13, 12, 23, 1, 32, 2, 3 and 6 among the nine fields of the grid below so the product of the three numbers in each row, each column and each of the two diagonals is the same.

A grid consisting of three rows of three blank squares each.

Spektrum der Wissenschaft, restyled by Amanda Montañez

The product of all nine numbers is 16 × 13 × 12 × 23 × 1 × 32 × 2 × 3 × 6 = 1, so the product of each of the eight expressions should also be 1. There are a total of eight possibilities in which three of these numbers result in the product 1. These are 16 × 1 × 6, 16 × 2 × 3, 13 × 12 × 6, 13 × 1 × 3, 13 × 32 × 2, 12 × 23 × 3, 12 × 1 × 2 and 23 × 1 × 32. The middle field of the square is included in four expressions; because 1 is the only number that appears in four possibilities, it must be in the middle field. The corners of the square belong to three expressions each, and because 13, 12, 2 and 3 only appear three times each, these numbers must be on the corner squares. The rest is straightforward—there is just one solution, apart from mirroring and rotating the pattern.

A grid consisting of three rows of three squares each with the following values filled in: first row: one third, three halves, 2; second row: 6, 1, one sixth; third row: one half, two thirds, 3.

Spektrum der Wissenschaft, restyled by Amanda Montañez

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This puzzle originally appeared in Spektrum der Wissenschaft and was reproduced with permission.

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