document.write( "Question 284296: What is the last digit of 7^2009 ? \r
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Algebra.Com's Answer #206299 by Edwin McCravy(20056) $\"\"$ $\"About$

You can put this solution on YOUR website!

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document.write( "So the last digits go in blocks of 4 like this:  7,9,3,1\r\n" );
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document.write( "So we just divide 2009 by 4\r\n" );
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document.write( "   502   \r\n" );
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document.write( "4)2009\r\n" );
document.write( "  20\r\n" );
document.write( "  --\r\n" );
document.write( "   009\r\n" );
document.write( "   008\r\n" );
document.write( "   ---\r\n" );
document.write( "     1  \r\n" );
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document.write( "That division tells us the last digits go \r\n" );
document.write( "through the cycle 7,9,3,1 502 times and the \r\n" );
document.write( "remainder, being 1, means that they end up \r\n" );
document.write( "on the first of the 503rd cycle and must \r\n" );
document.write( "therefore be a 7.\r\n" );
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document.write( "Edwin

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