Well, "a b c d e" are not "digits", but we'll treat them as if they are.
If repeating is OK, then there are 5 choices for each of the 4 'digits',
and the total number of possibilities is
5 x 5 x 5 x 5 = 625
there are 10 possibilities for the first spot, 9 for the second, 8 for the third 10x9x8=720 combinations
There are a lot of them, so I'm sure you don't want us to list them all. If you want 0-9, and are happy with repeat digits, then it's 10*10*10*10 = 10000 combinations. If it's 1-9 and are happy with repeat digits, then it's 9*9*9*9 = 6561 combinations. 0-9 without repeat digits is 10*9*8*7 = 5040 combinations 1-9 without repeat digits is 9*8*7*6= 3024 combinations
14
There are 15180 combinations.
-1
The first digit can be one of five integers (1 to 5) The second - fourth digits one of six integers (0 to 5). So: number of (valid) combinations is 5*6*6*6=1080 * * * * * This gives the number of permutations, not combinations. I am working on the latter.
If the digits can repeat, then there are 256 possible combinations. If they can't repeat, then there are 24 possibilities.
120 combinations using each digit once per combination. There are 625 combinations if you can repeat the digits.
there are 10 possibilities for the first spot, 9 for the second, 8 for the third 10x9x8=720 combinations
There are 36 possible characters (26 letters + 10 numbers) that can be used in each position of the 11-digit combination. Therefore, the total number of possible combinations is 36^11, which is approximately 7.52 x 10^17. This means there are over 750 quadrillion possible 11-digit combinations of letters A-Z and numbers 0-9 when combined.
If you can repeat the numbers within the combination there are 10,000 different combinations. If you cannot repeat the numbers within the combination, there are 5040 different combinations.
9
There are a lot of them, so I'm sure you don't want us to list them all. If you want 0-9, and are happy with repeat digits, then it's 10*10*10*10 = 10000 combinations. If it's 1-9 and are happy with repeat digits, then it's 9*9*9*9 = 6561 combinations. 0-9 without repeat digits is 10*9*8*7 = 5040 combinations 1-9 without repeat digits is 9*8*7*6= 3024 combinations
14
There are 15180 combinations.
-1
Oh, dude, you're hitting me with some math vibes here. So, if you have 6 digits to choose from to make a 4-digit combination, you can calculate that by using the formula for permutations: 6P4, which equals 360. So, like, you can make 360 different 4-digit combinations from those 6 digits. Math is wild, man.