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UKMT Junior Kangaroo, 2023

Number theory Difficulty 2.0 Junior Find the answer United Kingdom

Alisha wrote an integer in each square of a $4 \times 4$ grid. Integers in squares with a common edge differed by $1$ . She wrote a $3$ in the top left corner, as shown. She also wrote a $9$ somewhere in the grid. How many different integers did she write?

(A) $4$ (B) $5$ (C) $6$ (D) $7$ (E) $8$

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