2, 4, and 0?
Those are starting on 2-
204
240
Those are starting on 4
420
402
Those are starting on 0 (this is not a 3-digit number, but 2 digit number so not considered)
024
042
So totally, we have 4.
Simpler Solution:
2 (2 and 4) x 3 (3 digit numbers) - 2 (0)
6 - 2
4
and those are: 204, 240, 420, and 402.