Total number of different combination

[msa969]

I know that if you have 4 numbers eg. 1,23,4 then the total number fo diffferent combination is
4*3*2*1 = 24
what about if one number is the same eg. 1966

Thank you

 

[Stephen Tashi]

Are you asking about "permutations" or "combinations"?

 

[msa969]

so if I had the number 4573 what would be the total permutations?
and similarly 1966 total permutations

 

[DrClaude]

so if I had the number 4573 what would be the total permutations?

24, as you calculated.

and similarly 1966 total permutations

12. Imagine that the two sixes are different (e.g., different colors). You start by counting 4x3x2x1, but that means that you have overcounted because 6169 is the same as 6169. You then simply divide by two to remove the overcounting: 4! / 2 = 12.

 

[msa969]

colours makes perfect sense

 

[paulfr]

I believe you need to divide by 2 factorial, NOT 2.
Yes it is the same in this problem
But not if 3 or more are the same.