1/2+1/6+1/12+1/20.+1/380

网友回答

1/2+1/6+1/12+1/20.+1/380
=1/(1*2)+1/(2*3)+1/)3*4)+...+1/(19*20)
=1-1/2+1/2-1/3+1/3-1/4+...+1/19-1/20
=1-1/20
=19/20
======以下答案可供参考======
供参考答案1:
1/2=1/1-1/2
1/6=1/2-1-3
1/12=1/3-1/4
……1/380=1/19-1/20
1/2+1/6+1/12+1/20.....+1/380=/1-1/2
+1/2-1-3……+1/19-1/20=1-1/20=0.95
供参考答案2:
1/2+1/6+1/12+1/20.....+1/380
=1/1-1/2+1/2-1/3+1/3-1/4+...+1/19-1/20
=1-1/20
=19/20