Since there are three numbers from 8 to 10, there are six numbers to 13, nine numbers to 16, twelve numbers to 19, fifteen numbers to 22 and eighteen numbers to 25. By analogy, eight to twenty-eight is a * * * with twenty-one numbers. So the answer to the above question is that a * * has 2 1 numbers.

How to calculate a few numbers between a few and a few is to arrange them in order of natural numbers from small to large. The difference between every two adjacent numbers is 1, and the number from several to several is * * *. The calculation method is: large number and decimal number+1.