It is composed of numbers 1, 2, 3 and 4. Among the four digits without repetition, even numbers are common______ One

It is composed of numbers 1, 2, 3 and 4. Among the four digits without repetition, even numbers are common______ One

Even number, that is, the number of digits can only be 2 or 4. There are C21 · A33 = 2 × 3 × 2 × 1 = 12 at any other position, so the answer is: 12