1234
1243
1324
1342
1423
1432
2134
2143
2314
2341
2413
2431
3124
3142
3214
3241
3412
3421
4123
4132
4213
4231
4312
4321
720 of them.
The answer will depend on how many digits there are in each of the 30 numbers. If the 30 numbers are all 6-digit numbers then the answer is NONE! If the 30 numbers are the first 30 counting numbers then there are 126 combinations of five 1-digit numbers, 1764 combinations of three 1-digit numbers and one 2-digit number, and 1710 combinations of one 1-digit number and two 2-digit numbers. That makes a total of 3600 5-digit combinations.
ccsndf
There are 84 such numbers.
8 of them.
With 123 digits you can make 123 one-digit numbers.
12 numbers
Not sure what a "didget" is. It is possible to make 18 5-digit numbers.
8
720 of them.
162
5040
6, as long as they are all different
12,13,14 21,23,24 31,32,34 43,42,41 12 two-digit numbers
There are no three didgit numbers but there are 63 three digit numbers.
10999
24 if you don't repeat any numbers.24