This depends on whether you do mean sets or if you mean groups as the two are different and often people use the word set when they mean group. 24 groups can be formed and you can calculate this by using the permutation function. 4 possible elements to select from to go into 3 slots, 4P3=24 groups. (Note I said 4 elements not 5, as by definition an element can not be repeated in a set so the set is not {1,2,3,4,4} but {1,2,3,4} unless you mean {1,2,3,44} but this doesn't change anything.)
However, while 24 groups can be formed this is not true for sets, groups are structured unlike sets so a group of (1,2,3)≠(2,3,1), but a set{1,2,3}={2,3,1} i.e. the order of the elements matters in a group but not in a set, so only 6 sets of 3 elements can be made compared to 24 groups.
100,000
There are 504 such numbers.
12
823543
6
9999
100,000
There are 7,290 different 4-digit numbers that can be formed from the digits 1-9 without repetition.
There are 504 such numbers.
512
12
There are 5! = 120 such numbers.
The number 1234567890 can create about 39 of 40 4 digit numbers.
There are 60480 numbers.
823543
6
840