简便计算 1/2+1/4+1/8+1/16+1/32+1/64+1/108+1/216

问题描述:

简便计算 1/2+1/4+1/8+1/16+1/32+1/64+1/108+1/216

=1/2+1/4+(1/4-1/8)+(1/8-1/16)+(1/16-1/32)+(1/32-1/64)+(1/64-1/108)+(1/108-1/216)
=1/2+1/4+1/4-1/216
=1-1/216
=215/216