Answer:
17 numbers with any number of digits
12 numbers using as many digits as possible
Explanation:
It depends on how many digits you are required to use. If you're not required to use more than one digit, then the possible numbers are ...
0, 2, 8, 20, 28, 80, 82, 88,
208, 280, 288, 802, 808, 820, 828, 880, 882
for a total of 17 numbers.
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If you must use the maximum possible number of digits, then the 1-digit numbers and the 2-digit numbers containing 0 must be taken off the list, leaving ...
028, 082, 088, (and all the above 3-digit numbers)
for a total of 12 numbers.