One digit is right and in its place: 2
One digit is right but in the wrong place: 6.
Since the #6 is in slot 1 for lines #1 and #2, that leaves the #2 in the correct place.
The "two digits are right but both in the wrong place" is a "false qualifier?" All the digits are right, all in the wrong place.
So, we've got _, 6, 2.
The last line leaves 0.
It's clever. A mind twister. The #4 messes with my head a bit.