document.write( "Question 1154406: An addy number is a five digit number with these properties.
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Algebra.Com's Answer #776832 by Edwin McCravy(20060)\"\" \"About 
You can put this solution on YOUR website!
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document.write( "Let  1st digit  = x\r\n" );
document.write( "and  2nd digit  = y\r\n" );
document.write( "then 3rd digit  = x+y\r\n" );
document.write( "and  4th digit  = x+2y\r\n" );
document.write( "and  5th digit  = 2x+3y\r\n" );
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document.write( "No digit can be 0, since if x or y were 0, then x=y, which is not allowed,\r\n" );
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document.write( "If x=1,\r\n" );
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document.write( "1st digit = 1\r\n" );
document.write( "2nd digit = y\r\n" );
document.write( "3rd digit = 1+y\r\n" );
document.write( "4th digit = 1+2y\r\n" );
document.write( "5th digit = 2+3y\r\n" );
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document.write( "The 5th digit must be less than 10, so\r\n" );
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document.write( "2+3y < 10\r\n" );
document.write( "  3y < 8\r\n" );
document.write( "   y < 2 2/3, and it can't be 1, so y must be 2\r\n" );
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document.write( "so\r\n" );
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document.write( "1st digit = 1\r\n" );
document.write( "2nd digit = 2\r\n" );
document.write( "3rd digit = 3\r\n" );
document.write( "4th digit = 5\r\n" );
document.write( "5th digit = 8\r\n" );
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document.write( "So the first addy number is 12358\r\n" );
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document.write( "----\r\n" );
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document.write( "If x=2,\r\n" );
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document.write( "1st digit = 2\r\n" );
document.write( "2nd digit = y\r\n" );
document.write( "3rd digit = 2+y\r\n" );
document.write( "4th digit = 2+2y\r\n" );
document.write( "5th digit = 4+3y\r\n" );
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document.write( "The 5th digit must be less than 10, so\r\n" );
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document.write( "4+3y < 10\r\n" );
document.write( "  3y < 6\r\n" );
document.write( "   y < 2 so y must be 1\r\n" );
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document.write( "so\r\n" );
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document.write( "1st digit = 2\r\n" );
document.write( "2nd digit = 1\r\n" );
document.write( "3rd digit = 3\r\n" );
document.write( "4th digit = 4\r\n" );
document.write( "5th digit = 7\r\n" );
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document.write( "So the second addy number is 12358\r\n" );
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document.write( "------------------\r\n" );
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document.write( "If x=3,\r\n" );
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document.write( "1st digit = 3\r\n" );
document.write( "2nd digit = y\r\n" );
document.write( "3rd digit = 3+y\r\n" );
document.write( "4th digit = 3+2y\r\n" );
document.write( "5th digit = 6+3y\r\n" );
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document.write( "The 5th digit must be less than 10, so\r\n" );
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document.write( "6+3y < 10\r\n" );
document.write( "  3y < 4\r\n" );
document.write( "   y < 1 1/3 so y must be 1\r\n" );
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document.write( "so\r\n" );
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document.write( "1st digit = 3\r\n" );
document.write( "2nd digit = 1\r\n" );
document.write( "3rd digit = 4\r\n" );
document.write( "4th digit = 5\r\n" );
document.write( "5th digit = 9\r\n" );
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document.write( "So the third addy number is 31459\r\n" );
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document.write( "------\r\n" );
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document.write( "We have them all, because if x=4, the 5th digit, 2x+3y, would be at\r\n" );
document.write( "least 11, since y cannot be 0, and 11 is not a digit.\r\n" );
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document.write( "So there are only 3 addy numbers:\r\n" );
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document.write( "12358\r\n" );
document.write( "21347\r\n" );
document.write( "31459\r\n" );
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document.write( "Edwin

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