Let 5 digit numbers be constructed using the digits 0, 2, 3, 4, 7, 9 with repetition allowed, and are arranged in ascending order with serial numbers. Then the serial number of the number 42923 is _______ . [2023]
(2997)
Number starting with 2 and 3 =
Number starting with 40 =
Number starting with 420, 422, 423, 424, 427 =
Similarly, number starting with 4290 = 6