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Get the last digit (Posted on 2011-01-17) Difficulty: 2 of 5
Let A=2^n+3^n+7^n
For a given positive integer n what is the last digit of A?

See The Solution Submitted by Ady TZIDON    
Rating: 4.0000 (2 votes)

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Solution Solution | Comment 1 of 2
There may be a more compact way to state this but due to the repeating nature of the last digits of the powers of 2, 3, & 7,

the last digit of the sum is

8 for n mod4=3 or 0
2 for n mod4=1 or 2

  Posted by Kenny M on 2011-01-17 16:01:52
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