已知:1-1/2=1/2,1/2-1/3=1/6,1/3-1/4=1/12……你能很快算出1/2+1/6+1/12+1/20+1/3

问题描述:

已知:1-1/2=1/2,1/2-1/3=1/6,1/3-1/4=1/12……你能很快算出1/2+1/6+1/12+1/20+1/3

1/2+1/6+1/12+1/20+1/30
=1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6
=1-1/6
=5/6;