there are 63 combos
There are 15 combinations.
9999
98,706,816
40 dhjfdsm dlgkDRFRt
There are infinitely many numbers between any two different numbers. To get the number that is exactly in the middle, add the two numbers, then divide the result by 2.
120 WRONG! That is the number of PERMUTATIONS. In the case of combinations, the order of the numbers does not matter, so there is only 1 5-number combination from 5 numbers.
Only one, since the order of the numbers does not matter in a combination.
-- 4 numbers can be lined up in 24 different ways-- If the order doesn't matter, then there's only one4-number combination of 4 numbers.
10C6 = 210
There are 360 of them.
That depends on the manufacturer. Different brands can have different lengths of serial numbers.
There are 15 combinations.
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.
9999
Since there are infinitely many prime numbers, there can be no such number.
Different schemes have different id numbers of different lengths.
4 of them. In a combination the order of the numbers does not matter.