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Show that $14^n$ cannot end with the digit $0$ or $5$ for any natural number $n$.
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$14^n = 2^n \times 7^n$
To end with a digit $0$ or $5$, $14^n$ must have at least one prime factor $5$, which is not there.
$\therefore 14^n$ can not end with digit $0$ or $5$.
To end with a digit $0$ or $5$, $14^n$ must have at least one prime factor $5$, which is not there.
$\therefore 14^n$ can not end with digit $0$ or $5$.