Assuming that 00, 01, 02, etc. count as two digit numbers, then there are one hundred (1 through 99 and including 0).
If you are not allowed to count 00, 01, 02, 03, 04, 05, 06, 07, 08, or 09 because they simplify to one digit numbers, then you have ten less--so a total of ninety two digit numbers.
45
99999
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.
about 13
89,999 different numbers i guess
45
99999
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.
There are 60480 numbers.
There are 4^6 = 4096 such numbers.
Almost got me on this one. 20 numbers but 29 digits
If the digits are all different then 18. Otherwise, 192.
8.
about 13
89,999 different numbers i guess
There are 192.
∞ \ Infinite