-1/2-1/6-1/12-1/20-``````````````-1/4026042

=-[(1-1/2)+(1/2-1/3)+...+(1/2006-1/2007)]
=-(1-1/2007)
=-2006/2007

原式=-（1/2+1/6+1/12+1/20+....+1/4026042)
=-[(1-1/2)+(1/2-1/3)+(1/3-1/4)+(1/4-1/5+... (1/2006-1/2007)]
=-(1-1/2007)
=-2006/2007

原式=-(1/2+1/6+1/12+........+1/4026042)
=-(1-1/2+1/2-1/3+1/3-1/4+.........+1/2006-1/2007)
=-(1-1/2007)
=-2006/2007

这是什么意思，题目看不太懂，请把问题讲明白点