45
I assume you mean how many 4-digit numbers can be made from a set such as {A,A, B, C} where A, B and C are single digits. There are 12 such numbers.
162
about 13
they are 24 you can make with the numbers 1-4 or any other 4 digits here they are123412431432142313421324213421432431241323412314312431423421341232413214423142134312432141324123* * * * *WRONG!These are permutations, not combinations. In a combination theorder of the digits does not matter so there is only one combination of 4 digits out of 4.
94
45
I assume you mean how many 4-digit numbers can be made from a set such as {A,A, B, C} where A, B and C are single digits. There are 12 such numbers.
6
There are 7,290 different 4-digit numbers that can be formed from the digits 1-9 without repetition.
162
about 13
they are 24 you can make with the numbers 1-4 or any other 4 digits here they are123412431432142313421324213421432431241323412314312431423421341232413214423142134312432141324123* * * * *WRONG!These are permutations, not combinations. In a combination theorder of the digits does not matter so there is only one combination of 4 digits out of 4.
6: 146, 164, 416, 461, 614, and 641.
Assuming you mean permutations of three digits, then the set of numbers that can be made with these digits is: 345 354 435 453 534 543 There are six possible permutations of three numbers.
9
10