document.write( "Question 803431: for each integer n, its square can be written as n^2 = 10*k+r where r is an integer in the range 0 less than or equal to r less than or equal to 9.
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Algebra.Com's Answer #484356 by Edwin McCravy(20055)\"\" \"About 
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document.write( "n^2 = 10*k+r  0 < r < 9\r\n" );
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document.write( "r is the units (last) digit of a perfect square\r\n" );
document.write( "Since \r\n" );
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document.write( "0²=0\r\n" );
document.write( "1²=1, \r\n" );
document.write( "2²=4, \r\n" );
document.write( "3²=9\r\n" );
document.write( "4²=16\r\n" );
document.write( "5²=25\r\n" );
document.write( "6²=36\r\n" );
document.write( "7²=81\r\n" );
document.write( "8²=64\r\n" );
document.write( "9²=81\r\n" );
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document.write( "the last (units) digit of ALL perfect squares can\r\n" );
document.write( "only be 0,1,4,5,6, or 9.  Thus r can be\r\n" );
document.write( "0,1,4,5,6, or 9, r cannot be 2,3,7, or 8.\r\n" );
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document.write( "02 = 10(0) + 0\r\n" );
document.write( "12 = 10(0) + 1\r\n" );
document.write( "22 = 10(0) + 4\r\n" );
document.write( "32 = 10(0) + 9\r\n" );
document.write( "42 = 10(1) + 6\r\n" );
document.write( "52 = 10(2) + 5\r\n" );
document.write( "62 = 10(3) + 6\r\n" );
document.write( "72 = 10(4) + 9\r\n" );
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document.write( "Edwin

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