If the numbers are allowed to repeat, then there are six to the fourth power possible combinations, or 1296. If they are not allowed to repeat then there are only 360 combinations.
There are: 9C6 = 84 combinations
10 Combinations (if order doesn't matter). 3,628,800 Possiblilities (if order matters).
Oh, isn't that a happy little question? Let's see here... To find the number of combinations of 4 numbers out of 7, we can use a simple formula: 7 choose 4, which is calculated as 7! / (4! * (7-4)!). So, there are 35 unique combinations of 4 numbers that can be made from a set of 7 numbers. Isn't that just delightful?
There are 32C3 = 32*31*30/(3*2*1) = 4960 combinations. I do not have the inclination to list them all.
There are 167960 9 digits combinations between numbers 1 and 20.
The number of combinations of six numbers that can be made from seven numbers will depend on if you can repeat numbers. In all there are over 2,000 different numbers that can be made.
45
6
6
There are: 9C6 = 84 combinations
Twenty factorial which is denoted by "20!". 20! = 1x2x3x4x5x6x7x8x...x19x20
10
24
9!/5! or 3024
8C6 = 28
3! or 6 combinations can be made from three distinct numbers. For this example they are: 345, 354, 534, 543, 435, 453.
There are 167960 combinations.