1. First, make sure that 0 is a single digit, there are four choices for the decimal digit and only three choices for the percentile. 4X3= 12

2. Make sure that 2 is a single digit, and there are four choices for decimal digits (0, 1, 3, 4). The hundred digits at this time are (1, 3,4), (3,4), (1, 4) and (1, 4) respectively.

3. Similarly, when 4 is a single digit, there are nine situations. In this way, * * * 30 numbers.