document.write( "Question 792760: For each integer n, its square can be written uniquely as \"+n%5E2=10k%2Br+\", where r is an integer in the range 0 ≤ r ≤ 9. Determine which values of r can occur and which cannot. \n" ); document.write( "
Algebra.Com's Answer #514240 by Edwin McCravy(20056)\"\" \"About 
You can put this solution on YOUR website!
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document.write( "That's the same as asking\r\n" );
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document.write( "\"What digits can squares of integers end in?\"\r\n" );
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document.write( "and\r\n" );
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document.write( "\"What digits can squares of integers NOT end in?\"\r\n" );
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document.write( "The last digit of the product of any two\r\n" );
document.write( "integers is always the same digit as the\r\n" );
document.write( "last digit product of their last two \r\n" );
document.write( "digits.  So we look at these products:\r\n" );
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document.write( "0×0 = 0\r\n" );
document.write( "1×1 = 1\r\n" );
document.write( "2×2 = 4\r\n" );
document.write( "3×3 = 9\r\n" );
document.write( "4×4 = 16\r\n" );
document.write( "5×5 = 25\r\n" );
document.write( "6×6 = 36\r\n" );
document.write( "7×7 = 49\r\n" );
document.write( "8×8 = 64\r\n" );
document.write( "9×9 = 81\r\n" );
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document.write( "Those all end with 0,1,4,6,or 9\r\n" );
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document.write( "So r can be 0,1,4,6, or 9\r\n" );
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document.write( "So r cannot be 2,3,5,7, or 8\r\n" );
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document.write( "Edwin
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