There are 870 such numbers.
405
3
10*9*8=720
Integers of 6 digits are normally greater than integers of 5 digits
4 digits - representing 16 integers.
The sum of all the digits of all the positive integers that are less than 100 is 4,950.
279,999,720
50%
Three of them.
They are 13.
405
There are 21.
52
There are none.
Every number from 100 to 999 inclusive !
3
The sum of the digits is 6.