急！帮忙算一下！

其实很简单的！
1-1/2-1/4-1/8-…-1/512-1/1024
=1/2-1/4-1/8-…-1/512-1/1024
=1/4-1/8-…-1/512-1/1024
=1/8-…-1/512-1/1024
......
=1/512-1/1024
=1/1024

1/55+2/55+…+9/55+10/55-11/155-12/155-…-19/155-20/155
=(1+2+......+10)/55-(11+12+......+20)/155
=55/55-155/155
=0

1-1/2-1/6-1/12-1/20-1/30-1/42-1/56-1/72-1/90
=1-(1-1/2)-(1/2-1/3)-(1/3-1/4)-(1/4-1/5)-(1/5-1/6)-(1/6-1/7)-(1/7-1/8)-(1/8-1/9)-(1/9-1/10)
=1/10

10-3/2-5/4-9/8-17/16-33/32-65/64
=10-(1+1/2)-(1+1/4)-(1+1/8)-(1+1/16)-(1+1/32)-(1+1/64)
=4-(1/2+1/4+1/8+1/16+1/32+1/64)
=4-63/64
=3又1/64

9又3/4+99又3/4+999又3/4+9999又3/4+1
=9+99+999+9999+(3/4)*4+1
=9+99+999+9999+3+1
=(9+1)+(99+1)+(999+1)+(9999+1)
=10+100+1000+10000
=11110

1-1/2-1/4-1/8-…-1/512-1/1024=1/1024
1/55+2/55+…+9/55+10/55-11/155-12/155-…-19/155-20/155=0
1-1/2-1/6-1/12-1/20-1/30-1/42-1/56-1/72-1/90=1/10
10-3/2-5/4-9/8-17/16-