8999 a+890 b = 10C+99 1D

Because a, b, c, D *9= D, c, b, a.

So we know that a =1; Ding =9

Substitute 8999a+890b =10c+991d.

Get 8999+890b =10c+8919.

C =89 B +8

Because a, b, c and d are all numbers from 0 to 9.

So b = 0；; C =8

A, b, c, D = 1089 times 9 to get 980 1= D, c, b, a.