The predecessor of smallest four digit number made using each of the digits 6, 2, 0, 8 only once is
2067
8026
2068
6208
The smallest four digit number made using each of the digits 6, 2, 0, 8 only once is 2068.
Its predecessor is 2068 - 1 = 2067
The successor of largest four digit number using each of the digits 7, 1, 0, 5 only once is