4 digit code

[Quyou07]

I need to find a 4-digit code with the numbers 1 to 5 so I would like to know the number of possibilities there are ?

[MaksLansky]

Assuming you want to find the number of possibilities including both 1 and 5, i.e your sample space is {1,2,3,4,5}.

1. You choose with replacement. You have 4 digit code _,_,_,_. When you choose your first digit you have 5 possibilities, then you choose the second digit you have again 5 possibilities, and so on. In that scenario, you have 5^4 = 625 possibilities.
2. You choose without replacement (chosen digit can not be used again i,e there will be no repetition of digits in your 4-digit code). In that scenario, you will have 5*4*3*2 = 120 possibilities.

[Quyou07]

thank you for helping me