OG 11 - Number Properties, Exponents

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OG 11 - Number Properties, Exponents

by albertrahul » Wed Jul 09, 2008 5:51 am
What is the units digit of (13)^4 (17)^2 (29)^3 ?

(A) 9
(B) 7
(C) 5
(D) 3
(E) 1

Please let me know what is the quickest way to solve these problems?

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by gxliu » Wed Jul 09, 2008 6:01 am
Just multiply the ones digit
13^4=3*3=9
9*3=27
7*3=21
Take the 1

17^2= 7*7=49
Take the 9

29^3=9*9=81
81*9=9
Take the 9
1*9*9=1 in the units digit