1/3*4+1/4*5+1/5*6+······+1/19*20简便方法计算_数学解答

1/3*4+1/4*5+1/5*6+······+1/19*20简便方法计算

人气：380 ℃　时间：2019-08-19 21:46:01

解答

1/3*4+1/4*5+1/5*6+······+1/19*20
=1/3-1/4+1/4-1/5+1/5-1/6+...+1/19-1/20
=1/3-1/20
=17/60