- #1
sutupidmath
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Homework Statement
Find the last digit of [tex]7^{123} [/tex]
Homework Equations
The Attempt at a Solution
[tex]7^{123} \equiv x(mod 10)[/tex]
123=12*10+3 Now, since in Z_10
[tex]7^{120 }\equiv 1 (mod 10)=> 7^{123} \equiv 7^3=343 mod 10=>343(mod 10)=3[/tex]
SO would the last digit be 3?