1/10+1/100+1/1000+1/10000+.+1/10000000000 = 1111111111/10000000000
所以1-1/10-1/100-1/1000-1/10000-.-1/10000000000=1－（1/10+1/100+1/1000+1/10000+.+1/10000000000）＝8888888889/10000000000