SOLUTION: What is the units digit of 3^2009? (a) 1 (b) 3 (c) 5 (d) 7 (e) 9

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Question 252364: What is the units digit of 3^2009?
(a) 1 (b) 3 (c) 5 (d) 7 (e) 9
Found 2 solutions by richwmiller, scott8148:
Answer by richwmiller(17219) About Me  (Show Source):
You can put this solution on YOUR website!
there are 960 digits
the first three are 344 and the last three are 683
What is the point of this exercise?

Answer by scott8148(6628) About Me  (Show Source):
You can put this solution on YOUR website!
3^0 = 1
3^1 = 3
3^2 = 9
3^3 = 27
3^4 = 81
3^5 = 243
3^6 = 729
3^7 = 2187

the pattern for the units digit repeats 1-3-9-7 (or 3-9-7-1 if you start at 3^1)

2009 / 4 = 502, with a remainder of 1

units digit of 3^2009 is the same as 3^1 ___ which is 3