What is the units digit of 7^2009 ?

Mathematics
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What is the units digit of 7 ^ 2009?

Jul 23rd, 2015

Thank you for the opportunity to help you with your question!

7^1 = 7 (ends with 7)
7^2 = 49 (ends with 9)
7^3 = 343 (ends with 3)
7^4 = 2,401 (ends with 1)
7^5 = 16,807 (ends with 7)
7^6 = 117,649 (ends with 9)
7^7 = 823,543 (ends with 3)
7^8 = 5,764,801 (ends with 1)

This pattern (7, 9, 3, 1) will repeat every 4 powers, so the last digit 7^2009 is same as 7^9

So last digit is 7

last unit digit of 7^2009 is 7.

Thanks

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Jul 23rd, 2015

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Jul 23rd, 2015
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