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UKMT Junior Kangaroo, 2022

Algebra Difficulty 1.0 Junior Find the answer United Kingdom

The sum $3 + 5 \times 7 - 9 = 36$ is incorrect. However, if one of the numbers is increased by 1, it becomes a correct calculation. Which number should be increased?

(A) $3$ (B) $5$ (C) $7$ (D) $9$ (E) $36$

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