well the first 9 digit number is 100 million 100,000,000
the last 9 digit number is 999 million 999,999,999
just minus the two numbers and you get... 899,999,999
so there are around 900 million 9 digit numbers.
9 digits number starting from100000000
9 digits number end from 999999999
9 digit number starting from 999999999
999-111=888 888 3 digit numbers can be made with numbers between 1 - 9
999
10C2 = 45
1000there aren't even 1000 three-digitnumbers...There are the digits 1 through 9 for the first digit. Then, we have 0 through 9 for the second digit - excluding the first digit. For the third digit, we have 0 through 9, excluding the two previous digits for a total of 9*9*8 =81*8 =648 three digit numbers with distinct digits.EDIT- ... to be a little more specific, if your talking about a 3-digit password or unlock code its would be 1000. _-_
9
There are 9 digits that can be the first digit (1-9); for each of these there is 1 digit that can be the second digit (6); for each of these there are 10 digits that can be the third digit (0-9); for each of these there are 10 digits that can be the fourth digit (0-9). → number of numbers is 9 × 1 × 10 × 10 = 900 such numbers.
There are 16 4-digit numbers that can be made up from 9 and 6.
900 numbers
999-111=888 888 3 digit numbers can be made with numbers between 1 - 9
There are 9000 4-digit numbers. 8*9*9*9 = 5832 of them do not contain a 5 The remaining 3168 contain a 5.
9
It would help to know which digit. 0 appears in 9 numbers and each of the others in 18 numbers.
You can select 9 numbers for the first digit, 8 numbers for the second digit, and 7numbers for the third digit; so 504 (e.g. 9*8*7) different three digit numbers can be written using the digits 1 through 9.
10,000
100,000
There are 9*10*9 = 810 such numbers.
999