(1/10+1/100+1/1000+1/10000)/(1/100+1/1000) =(1/10+1/100+1/1000+1/10000)X10000/[(1/100+1/1000)X10000] =(1000+100+10+1)/(100+10) =1111/110 =101/10 如果本题有什么不明白可以追问,,8,
