Question: Units Digit of 53 to Power of 35

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Comment on Units Digit of 53 to Power of 35

What do you advise?

Of the (13^5)(15^4)(17^5)
(13)^5 = Odd
(17)^5 = Odd
(15)^4 = Unit digit of 5
5*Odd = Unit of 5
gmat-admin's picture

That's a great approach!

A simple way of thinking about this for me is to find the cycle, in this case 4 (3, 9, 7, 1), then divide the exponent by the cycle, 4. 35/4 = 32 R 3, therefore the answer is the 3rd digit in the cycle. If R is 0 then the answer will be the last digit in your cycle.
gmat-admin's picture

Perfect!

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