a   b            c         d        e
1 9               9     555564    x-1
2 99             11     555566    x+1
3 999           111     555666    x2+x+1
4 9999          101     555656    x2+1
5 99999       11111     566666    x4+x3+x2+x+1
6 999999         91     555646    x2-x+1