How many even four digit numbers () A. 6B. 10C. 12D. 24
When the last digit is 0, the first three digits are randomly arranged with A33 = 6. When the last digit is 2, the first digit can only be selected from 1 and 3, and then the middle two digits are arranged with A12 · A22 = 4. According to the principle of classification and counting, there are 6 + 4 = 10 even digits without repetition