1/2+3/4+7/8+15/16加31/32加63/64+127/128加255/256
=1-1/2+1-1/4+1-1/8+1-1/16+...+1-1/256
=(1+1+...+1)-(1/2+1/4+1/8+...+1/256)
=8-255/256
=7又1/256
解:
=1/2+1-1/4+1-1/8+1-1/16+1-1/32+1-1/64+1-1/128+1-1/256
=7+1/2-(1/4+1/8)-(1/16+1/32)-1/64-(1/128+1/256)
=7+1/2-3/8-3/32-1/64-3/256
=7+1/8-3/32-1/64-3/256
=7+1/32-1/64-3/256
=7+1/256
=7又1/256。