Chat with our AI personalities
.0123456789
There are 76 such numbers. Eight more if you allow numbers to start with 0.
-- The first digit can be any one of nine. (It can't be zero).-- The second digit can be any one of nine. (Anything except the one you used for the first digit.)-- The third digit can be any one of eight. (Anything except the two already used.)Total possibilities = (9 x 9 x 8) = 648
If a leading zero is allowed... The first digit can be 0-9, ten possibilities. The second digit can be 0-9, ten possibilities. The third digit can be 0-9, ten possibilities. The fourth digit can be 3-9, 7 possibilities. So there are 10x10x10x7 = 7000 such codes.
0123456789