Question

计算题 简算 急求二分之一加四分之三加八分之七加十六分之十五加三十二分之三十一加六十四分之六十三加一百二十八分之一百二十

Answer 1

1/2+3/4+7/8+15/16+31/32+63/64+127/128+255/256

=(1-1/2)+(1-1/4)+(1-1/8)+(1-1/16)+……+(1-1/256)

=8-(1/2+1/4+1/8+……+1/256)

=8-(1/2+1/4+1/8+……+1/256+1/256-1/256)

=8-(1-1/256)

=8-255/256

=7又1/256