就今天晚上!最好9:05之前1 +(1/2-1)+(1/3-1/2)+(1/4-1/3).(1/2009-1/2008)+(1/2010-1/2009)

问题描述:

就今天晚上!最好9:05之前1 +(1/2-1)+(1/3-1/2)+(1/4-1/3).(1/2009-1/2008)+(1/2010-1/2009)

这类题都有许多了
原式=1-1+1/2-1/2+1/3-1/3+1/4-.-1/2008+1/2009-1/2009+1/2010
=1/2010