Formula: nPr
where n is the number of things to choose from and you choose r of them
17P3 = 17!/ (17-3)! = 4080
There are: 17C5 = 6188
If they can repeat, then: 17^6=24,137,569 If they can't repeat, then: 17*16*15*14*13*12=8,910,720
How many combinations of five. Numbers could you get from 1 to 20
There are 17 I think
Three possible combinations: 17+1, 13+5 and 7+11.
017, 071, 107, 170, 701, 710. 6 combinations
There are many possible solutions. One of these is {7, 17, 17, 17, 17}
There are 18C4 = 18!/[18-4)!4!] = 18*17*16*15/(4*3*2*1) = 3060 combinations.
Assuming you are using "combinations" in the mathematical sense where order doesn't matter (if order does matter it would be "permutations"), there are 22C5 = 22!/5!17! = 26,334 possible combinations of 5 numbers from 22. They start {1, 2, 3, 4, 5}, {1, 2, 3, 4, 6}, {1, 2, 3, 4, 7}, ... and end ... {16, 19, 20, 21, 22}, {17, 19, 20, 21, 22}, {18, 19, 20, 21, 22}; I'll leave the 26,328 combinations in the middle for you to list.
The first number has 19 possibilities. The second has 18, and the third only 17. 19x18x17=5814 possible lock combinations. (If you could repeat, it would be 19x19x19=6859)
There are infinitely many possible answers. One such is 3.45 + 2.59 + 10.96 = 17
21