SOLUTION: How many 4-digit even numbers can be created from the digits {0, 1, 2, 3}?

Any of the 3 digits 1, 2, 3 in the left-most position;


any of 4 digits in the next position


    . . . and so on . . . 


give finally   = 3*64 = 192 possible 4-digit numbers satisfying the imposed conditions.