This would be a permutation question.
We have 4 choices, 0, 3, 7, 8
As we wish to make a 4-digit number abcd.
For d, the units, we have 2 choices, 3 or 7.
And for each of the other digits, a,b,c we have 4 choices, 0,3,7,8.
Hence the our total number of choices are 4x4x4x2