document.write( "Question 972066: find the missing number in the following series: 3, 14, 27, ?, 63, 86, 115 \n" ); document.write( "
Algebra.Com's Answer #594700 by Edwin McCravy(20056)\"\" \"About 
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document.write( "3, 14, 27, ?, 63, 86, 115\r\n" );
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document.write( "Form the first and second differences.\r\n" );
document.write( "Subtract each number from the one to the right of\r\n" );
document.write( "it and write it underneath the number.  For instance\r\n" );
document.write( "the 11 came from subtracting 14-3 getting 11 and \r\n" );
document.write( "writing 11 underneath 3.  And when there is no number\r\n" );
document.write( "to subtract write a question mark there:\r\n" );
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document.write( "  3, 14, 27, ?, 63, 86, 115\r\n" );
document.write( " 11, 13, 16, ?, 23, 29\r\n" );
document.write( "  2,  3,  ?, ?,  6\r\n" );
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document.write( "The bottom line seems to go 2, 3, 4, 3, 6, 3, 8, 3, 10, 3, 12, 3, ...\r\n" );
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document.write( "So we can put 4 and 3 where the bottom two question marks are, \r\n" );
document.write( "then work backwards and get 20 between the 16 and the 23 on the\r\n" );
document.write( "middle row, and that makes the missing number on the top row 43.\r\n" );
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document.write( "  3, 14, 27, 43, 63, 86, 115\r\n" );
document.write( " 11, 13, 16, 20, 23, 29\r\n" );
document.write( "  2,  3,  4,  3,  6\r\n" );
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document.write( "Answer: 43\r\n" );
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document.write( "Edwin
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