document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=252456>Question 252456</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Evaluate the sum: 1-2+3-4+5-6+7-8+9-10+…-998+999-1000 </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #184373 by </B><A HREF=/tutors/aboutme.mpl?userid=drk><B>drk(1908)</B></A><img src=\"/images/stars/stars-12.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=drk><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/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=184373\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Evaluate the sum: 1-2+3-4+5-6+7-8+9-10+…-998+999-1000<BR>\n" );
document.write( "Notice that each pair of number adds to -1.<BR>\n" );
document.write( "There are 500 such pairs, so,\r<BR>\n" );
document.write( "\n" );
document.write( "500*(-1) = -500. </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );