1/2*3+1/3*4+1/4*5+1/5*6+1/6*7+1/7*8+1/8*9+1/9*10+1/10*11(简算)

问题描述:

1/2*3+1/3*4+1/4*5+1/5*6+1/6*7+1/7*8+1/8*9+1/9*10+1/10*11(简算)

原式=1/2-1/3+1/3-1/4+1/5-1/6+……+1/10-1/11
=1/2-1/11
=9/22