Answer:
2673
Explanation:
The expression 9cube×4 is counting some numbers like 0300, which are less than 1000. We can fix this as the first digit could be 3, which gives us 9cube possibilities.
The second, third, and fourth digits could be 3, and each of these cases gives us 8×9Square possibilities. (The first digit cannot be 0.)
So the total number of possibilities is
9Cube +8×9Square×3=2673.