The rule that a number is divisible by 2 is: the last digit is 0, 2, 4, 6, 8; And as long as it is two consecutive natural numbers, one of them must be divisible by 2.

So a * * * has: 100/2=50.

The rule that can be divisible by 9 is that the sum of each number can be divisible by 9, so there are:

9, 18,27,36,45,54,63,72,8 1,90,99

A *** 1 1

So: 50+ 1 1-5=56 is divisible by 2 or 9.