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UKMT Senior Mathematical Challenge, 2016

Number theory Difficulty 2.0 Junior Find the answer United Kingdom

All the digits 2, 3, 4, 5 and 6 are placed in the grid, one in each cell, to form two three-digit numbers that are squares. Which digit is placed in the centre of the grid?

(A) $2$ (B) $3$ (C) $4$ (D) $5$ (E) $6$

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