UKMT Pink Kangaroo, 2021

Number theory Difficulty 2.0 Junior Find the answer United Kingdom

Each of the numbers $m$ and $n$ is the square of an integer. The difference $m - n$ is a prime number. Which of the following could be $n$ ?

(A) $100$ (B) $144$ (C) $256$ (D) $900$ (E) $10000$

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