document.write( "Question 1138837: What is the units digit of 7^2019? \n" ); document.write( "
Algebra.Com's Answer #756625 by Edwin McCravy(20063)\"\" \"About 
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What is the units digit of 7^2019?
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document.write( "The units digit of 7 is 7\r\n" );
document.write( "The units digit of 7×7=49 is 9\r\n" );
document.write( "The units digit of 9×7=63 is 3\r\n" );
document.write( "The units digit of 3×7=21 is 1\r\n" );
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document.write( "The units digit of 1×7=7 is 7 again. \r\n" );
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document.write( "So the units digits of the\r\n" );
document.write( "powers of 7 go 7,9,3,1,7,9,3,1,7,9,3,1,...\r\n" );
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document.write( "They go in groups of 4,\r\n" );
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document.write( "   504\r\n" );
document.write( "4)2019\r\n" );
document.write( "  20\r\n" );
document.write( "    19\r\n" );
document.write( "    16\r\n" );
document.write( "     3\r\n" );
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document.write( "The quotient is 504 and the remainder is 3. So the units digit of 72019 will \r\n" );
document.write( "be the 3rd in the 504th group of four 7,9,3,1, and so it will be 3.\r\n" );
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document.write( "Edwin
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