Multiple choice general knowledge math & puzzles

If A is an even number, then the unit digit of A^(4n - 4), in case n>1 , will always be

  1. 0

  2. 4

  3. 6

  4. 0 or 6
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

If A is even, A^k ends in 6 if k is a multiple of 4 (except for A ending in 0). If A ends in 0, A^k ends in 0. Since 4n-4 is a multiple of 4 for n>1, the unit digit must be 0 or 6.

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