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You can put this solution on YOUR website!
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document.write( "Let the numbers \"to carry\" be t, u, v, and w that I've written above\r\n" );
document.write( "the addition:\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "tuvw\r\n" );
document.write( " SEND\r\n" );
document.write( "+MQRE\r\n" );
document.write( "-----\r\n" );
document.write( "MQNEY\r\n" );
document.write( "\r\n" );
document.write( "The numbers \"to carry\" are either 0 or 1. Since the letter O looks like the\r\n" );
document.write( "digit 0 (zero), I will use Q instead to avoid confusion.\r\n" );
document.write( "\r\n" );
document.write( " Obviously t = M = 1, so we have\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "1uvw\r\n" );
document.write( " SEND\r\n" );
document.write( "+1QRE\r\n" );
document.write( "-----\r\n" );
document.write( "1QNEY\r\n" );
document.write( "\r\n" );
document.write( "Case 1: u=1\r\n" );
document.write( "\r\n" );
document.write( "11vw\r\n" );
document.write( " SEND\r\n" );
document.write( "+1QRE\r\n" );
document.write( "-----\r\n" );
document.write( "1QNEY\r\n" );
document.write( "\r\n" );
document.write( "Then S = 8, Q = 9\r\n" );
document.write( "\r\n" );
document.write( "11vw\r\n" );
document.write( " 8END\r\n" );
document.write( "+10RE\r\n" );
document.write( "-----\r\n" );
document.write( "10NEY\r\n" );
document.write( "\r\n" );
document.write( "This makes v=1 to prevent E=N\r\n" );
document.write( "But in order to cause a carry of 1,\r\n" );
document.write( "E could only be 9, causing N=0\r\n" );
document.write( "but Q is already 0. That rules\r\n" );
document.write( "out case u=1.\r\n" );
document.write( "\r\n" );
document.write( "So u=0\r\n" );
document.write( "\r\n" );
document.write( "10vw\r\n" );
document.write( " SEND\r\n" );
document.write( "+1QRE\r\n" );
document.write( "-----\r\n" );
document.write( "1QNEY\r\n" );
document.write( "\r\n" );
document.write( "so S=9, Q=0\r\n" );
document.write( "\r\n" );
document.write( "10vw\r\n" );
document.write( " 9END\r\n" );
document.write( "+10RE\r\n" );
document.write( "-----\r\n" );
document.write( "10NEY\r\n" );
document.write( "\r\n" );
document.write( "v=1 to prevent E=N\r\n" );
document.write( "\r\n" );
document.write( "101w\r\n" );
document.write( " 9END\r\n" );
document.write( "+10RE\r\n" );
document.write( "-----\r\n" );
document.write( "10NEY\r\n" );
document.write( "\r\n" );
document.write( "E + 1 = N\r\n" );
document.write( "w + N + R = 10 + E\r\n" );
document.write( "D + E = Y + 10w\r\n" );
document.write( "\r\n" );
document.write( "Try w=0\r\n" );
document.write( "\r\n" );
document.write( "E + 1 = N\r\n" );
document.write( "N + R = 10 + E\r\n" );
document.write( "D + E = Y \r\n" );
document.write( "\r\n" );
document.write( "Substitute E + 1 for N in the second equation\r\n" );
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document.write( "E + 1 + R = 10 + E\r\n" );
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document.write( "That simplifies to\r\n" );
document.write( "\r\n" );
document.write( "R = 9\r\n" );
document.write( "\r\n" );
document.write( "But S = 9,\r\n" );
document.write( "\r\n" );
document.write( "so w = 1\r\n" );
document.write( "\r\n" );
document.write( "1011\r\n" );
document.write( " 9END\r\n" );
document.write( "+10RE\r\n" );
document.write( "-----\r\n" );
document.write( "10NEY\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "N + R = E + 9\r\n" );
document.write( "1 + E = N\r\n" );
document.write( "D + E = Y + 10\r\n" );
document.write( "\r\n" );
document.write( "Substitute 1 + E for N in the 1st equation\r\n" );
document.write( "\r\n" );
document.write( "1 + E + R = E + 9\r\n" );
document.write( " R = 8\r\n" );
document.write( "\r\n" );
document.write( "1011\r\n" );
document.write( " 9END\r\n" );
document.write( "+108E\r\n" );
document.write( "-----\r\n" );
document.write( "10NEY\r\n" );
document.write( "\r\n" );
document.write( "E + 1 = N\r\n" );
document.write( "D + E = Y + 10\r\n" );
document.write( "\r\n" );
document.write( "0 and 1 are used, so Y > 1, so\r\n" );
document.write( "\r\n" );
document.write( "D + E > 11\r\n" );
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document.write( "So the only possibility is\r\n" );
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document.write( "{D,E} = {6,7} or {D,E} = {5,7}\r\n" );
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document.write( "Try {D,E} = {6,7}\r\n" );
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document.write( "So Y = 3\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "1011\r\n" );
document.write( " 9END\r\n" );
document.write( "+108E\r\n" );
document.write( "-----\r\n" );
document.write( "10NE3\r\n" );
document.write( "\r\n" );
document.write( "But E has to be 1 more than E\r\n" );
document.write( "E can't be 7 because that would make N=8=R. \r\n" );
document.write( "E can't be 6 because that would make N and D \r\n" );
document.write( "both be 7.\r\n" );
document.write( "\r\n" );
document.write( "So \r\n" );
document.write( "\r\n" );
document.write( "{D,E} = {5,7} which makes Y = 2\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "1011\r\n" );
document.write( " 9END\r\n" );
document.write( "+108E\r\n" );
document.write( "-----\r\n" );
document.write( "10NE2\r\n" );
document.write( "\r\n" );
document.write( "Since N is 1 more than E, E can't be 7,\r\n" );
document.write( "for that would make N=8=R, so E=5, and D=7\r\n" );
document.write( "\r\n" );
document.write( "1011\r\n" );
document.write( " 95N7\r\n" );
document.write( "+1085\r\n" );
document.write( "-----\r\n" );
document.write( "10N52\r\n" );
document.write( "\r\n" );
document.write( "So N=6\r\n" );
document.write( "\r\n" );
document.write( "1011\r\n" );
document.write( " 9567\r\n" );
document.write( "+1085\r\n" );
document.write( "-----\r\n" );
document.write( "10652\r\n" );
document.write( "\r\n" );
document.write( "Whew!\r\n" );
document.write( "\r\n" );
document.write( "Edwin \n" );
document.write( "