if you can start with 0, there are 5 x 4 x 3 x 2 = 120 combinations.
if you can't start with 0 then 4 x 4 x 3 x 2 = 96 combinations
128
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.
There are 9999 possible combinations starting from 0000 to 9999
There are 15, and they are:1234 1235 1236 1245 1246 1256 1345 1346 1356 1456 2345 2346 2356 2456 3456.
Assuming you are using the standard English alphabet, the number of combinations you can make are: 26 x 26 = 676 combinations.
128
There are infinitely many numbers and so infinitely many possible combinations.
24680
140 possible combinations
In a 7 segment display, the symbols can be created using a selected number of segments where each segment is treated as a different element.When 1 segment is used, the possible positions are 7because it can be any of the 7 segments (7C1=7).When 2 segments are used, the number of possible combinations are 7C2=21.When 3 segments are used, the number of possible combinations are 7C3=35When 4 segments are used, the number of possible combinations are 7C4=35When 5 segments are used, the number of possible combinations are 7C5=21When 6 segments are used, the number of possible combinations are 7C6=7When 7 segments are used, the number of possible combinations are 7C7=1Adding the combinations, 7+21+35+21+7+1=127Therefore, 127 symbols can be made using a 7 segment display!
There are twelve possible solutions using the rule you stated.
24680 using only even numbers or 12346 which is an even number
im assuming that any charcter can be a number or a letter: (24letters*10 possible numbers)^(4 digits)= 3317760000 possible combinations.
If the digits can repeat, then there are 256 possible combinations. If they can't repeat, then there are 24 possibilities.
There are 5,040 combinations.
3,124,550 possible combinations
The answer is five factoral (5!) which is 120.