必须根据小学的理解力来解题,高等方法不被接受
1/2+1/4+1/8+1/16+1/32+1/64+1/128
=(1/2+1/4+1/8+1/16+1/32+1/64+1/128+1/128)-1/128
=(1/2+1/4+1/8+1/16+1/32+1/64+1/64)-1/128
=(1/2+1/4+1/8+1/16+1/32+1/32)-1/128
=(1/2+1/4+1/8+1/16+1/16)-1/128
=(1/2+1/4+1/8+1/8)-1/128
=(1/2+1/4+1/4)-1/128
=(1/2+1/2)-1/128
=1-1/128
=127/128