document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1201805>Question 1201805</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Find the value of 1-2+3-4+4-6+...-100 </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #836312 by </B><A HREF=/tutors/aboutme.mpl?userid=greenestamps><B>greenestamps(13200)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=greenestamps><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=greenestamps><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=836312\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <br><BR>\n" );
document.write( "Find the value of 1-2+3-4+<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=cross%284%29 ALIGN=MIDDLE  ALT=\"cross%284%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >5-6+...-100<br><BR>\n" );
document.write( "Presumably that is the expression you need to evaluate.  It doesn't take a lot of effort to look at what you are posting before you post it, to see it you are posting it correctly....<br><BR>\n" );
document.write( "1-2+3-4+5-6+...+99-100<br><BR>\n" );
document.write( "Group the terms in pairs:<br><BR>\n" );
document.write( "(1-2)+(3-4)+(5-6)+...+(99-100)<br><BR>\n" );
document.write( "(-1)+(-1)+(-1)+...+(-1)<br><BR>\n" );
document.write( "That's 50 pairs, each with a sum of -1, so the sum of all the numbers is 50(-1) = -50.<br><BR>\n" );
document.write( "ANSWER: -50<br><BR>\n" );
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