None. The sum of one digit can't be twice the size of the digit.
Only one . . . . . 18
10 digits are numbers in the billions.
24.
there are 899 whole numbers that have three digits.
99999
Only one . . . . . 18
Excluding numbers which begin with 0, there are 67,200 of them.
10 digits are numbers in the billions.
24.
there are 899 whole numbers that have three digits.
525
two
99999
There are 5 numbers of 1 digit, 25 numbers of 2 digits, and 75 numbers of 3 digits. This makes 105 numbers in all.
how many numbers exactly have 4 digits ? 8900, 8999, 9000, 9999
5*4*3*2 = 120
17 digits