计算1/2*1/3+1/3*1/4+1/4*1/5+1/5*1/6+.+1/10*1/11

问题描述:

计算1/2*1/3+1/3*1/4+1/4*1/5+1/5*1/6+.+1/10*1/11

1/2*1/3+1/3*1/4+1/4*1/5+1/5*1/6+.+1/10*1/11
=1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+.+1/10-1/11
=1/2-1/11
=9/22