Question

The digit in the unit place of the product (2137) ^754 is ?
(a) 1
(b) 3
(c) 7
(d) 9
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Answer 1

Answer:

7 powers unit digit 7^1=unit digit 7

7^2=unit digit 9

7^3=unit digit 3

7^4= unit digit 1

7,9,3,1 these unit digits repeat

754/4 remainder is 2

therefore 2137^754 unit digit= 9