Posted by shirley on .
how many combinations can you get with 1 2 3 4 5?

math 
drwls,
Combinations of how many numbers? Don't you mean permutations?
If 1,2,3,4 and 5 are your only five numbers and you must pick five, and if the order does not matter, then there is only one combination. 
math 
drwls,
I should have also asked how many times the same number can be picked. I assumed only once.

math 
Damon,
I assume that all of the elements are included in each combination (you can not use 132 ignoring 4 and 5 for example)
In that case the question is how many arrangements can be made of n things taken n at a time which is the permutations of n elements taken r at a time where here r = n = 5
That implies that each element is used only once
0! = 1 by the way
P(n,r) = n!/(nr)!
P (5,5) = 5!/0! = 5*4*3*2*1 =20*6 = 120
In other words I have 5 choices for the first number
four choices for the second number
3 choices for the third
2 for the fourth
and only one for the last 
math 
Damon,
If you really mean "combinations" then Dr WLS has it right. If there is no matter the order (combinations) then there is only one combination
but
I suspect you mean permutations.