111111111/9 =(100000000+10000000+1000000...)/9 =(999999999+9999999+999999+99999+9999+999+99+9+1*9)/9 =111111111+11111111+1111111+...+111+11+1+1 =12345678+1 =12345679 规律是 123456789*9=1111111101 1234...