I'm just wondering, what is the total number of $4$ digit positive integers that have the following properties:
All digits are unique.
Does not contain the digits $3$ and/or $4.$
The number is divisible by $3.$
Thoughts: All digits are unique is $9\times9\times8\times7,$ as I have learned, and I don't know how to do the second and third ones, to eliminate the ones that doesn't have this property.