Eight: 111 116 161 166 611 616 661 666.
There are 38760 combinations.
45.
5
There would be 9*9*9*9 or 6561 combinations.
-8
Number of 7 digit combinations out of the 10 one-digit numbers = 120.
There are 38760 combinations.
The answer will depend on how many digits there are in each of the 30 numbers. If the 30 numbers are all 6-digit numbers then the answer is NONE! If the 30 numbers are the first 30 counting numbers then there are 126 combinations of five 1-digit numbers, 1764 combinations of three 1-digit numbers and one 2-digit number, and 1710 combinations of one 1-digit number and two 2-digit numbers. That makes a total of 3600 5-digit combinations.
There are 1140 five digit combinations between numbers 1 and 20.
If you are able to repeat numbers you would take 6 * 6 * 6 = 216 combinations. If you are not able to repeat numbers you would take 6 * 5 * 4 = 120 combinations.
There are 840 4-digit combinations without repeating any digit in the combinations.
You would get 4!/2! = 12 combinations.
7
56 combinations. :)
Any 6 from 51 = 18,009,460 combinations
5
45.