You Can Create 999 Number combinations
9999
There are infinite combinations that can make 3879
Assuming the digits cannot be repeated, there are 7 combinations with 1 digit, 21 combinations with 2 digits, 35 combinations with 3 digits, 35 combinations with 4 digits, 21 combinations with 5 digits, 7 combinations with 6 digits and 1 combinations with 7 digits. That makes a total of 2^7 - 1 = 127: too many for me to list. If digits can be repeated, there are infinitely many combinations.
1
There is only one combination. The order of the digits in combinations makes no difference. They are considered as being different if they are permutations, not combinations.
There are only 10 combinations. In each combination one of the 10 digits is left out.
Since a number can have infinitely many digits, there are infinitely many possible combinations.
Yuo can make only one combination of 30 digits using 30 digits.
Assuming you can repeat digits (like the number 1228 for example), there are 84 = 4096.If you can't repeat digits then it is equivalent to 8!/4! = 1680.
To calculate the number of 4-number combinations using the numbers 1, 2, 3, 4, and 5 without repetition, you can use the formula for permutations. Since order matters in a combination, you would use the formula for permutations, which is nPr = n! / (n - r)!. In this case, you would have 5 choices for the first number, 4 choices for the second number, 3 choices for the third number, and 2 choices for the fourth number. Therefore, the total number of 4-number combinations would be 5P4 = 5! / (5-4)! = 5 x 4 x 3 x 2 = 120 combinations.
6 for 3-digits, 6 for 2-digits, 3 for 1-digits, and 15 for all of the combinations
With repeating digits, there are 33 = 27 possible combinations.Without repeating any digits, there are 6 combinations:357375537573735753
0000-9999 (10x10x10x10 or 104) = 10,000 possible combinations allowing for repeated digits. If you are not able to repeat digits then it's 10 x 9 x 8 x 7 or 5,040 possible combinations without repeated digits.
You Can Create 999 Number combinations
The order of the digits in a combination does not matter. So 123 is the same as 132 or 312 etc. There are 10 combinations using just one of the digits (3 times). There are 90 combinations using 2 digits (1 once and 1 twice). There are 120 combinations using three different digit. 220 in all.
If each number can be used only once then there are just four: 2345, 2346, 2456 and 3456. There are no others because the order of the digits does not matter in combinations.