document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1209331>Question 1209331</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Hi<BR>\n" );
document.write( "Find the value of 1-2+3-4+5-6+.....+2007-2008+2009-2010+2011. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #848380 by </B><A HREF=/tutors/aboutme.mpl?userid=ikleyn><B>ikleyn(52858)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=ikleyn><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/cgi-bin/show-face.mpl?user=ikleyn><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=848380\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> .\r<BR>\n" );
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document.write( "This problem admits simple mathematical mental solution.\r<BR>\n" );
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document.write( "Group the terms in pairs\r<BR>\n" );
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document.write( "1-2+3-4+5-6+.....+2007-2008+2009-2010+2011 = (1-2)+(3-4)+(5-6)+.....+(2007-2008)+(2009-2010)+2011.\r<BR>\n" );
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document.write( "You have 2010/2 = 1005 pairs and the last unpaired term 2011.\r<BR>\n" );
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document.write( "Each pair produces -1, so the total expression is -1005+2011, and you can calculate it mentally.\r<BR>\n" );
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document.write( "<U>ANSWER</U>.  &nbsp;&nbsp;1006.\r<BR>\n" );
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document.write( "Solved &nbsp;(mentally)\r<BR>\n" );
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document.write( "This problem is specially designed to be solved in this way.\r<BR>\n" );
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document.write( " </SPAN>\n" );
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