1/2*1/3+1/3*1/4+1/4*1/5+1/5*1/6 (简便方法)

问题描述:

1/2*1/3+1/3*1/4+1/4*1/5+1/5*1/6 (简便方法)

1/2*1/3+1/3*1/4+1/4*1/5+1/5*1/6
=1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6
=1/2-1/6
=1/3