There are 6 groups.
If the six numbers are all different, then the answer is 6C4 = 6*5/(2*1) = 15
2 groups
5
If the order of the 4 numbers matters, then there are (6 x 5 x 4 x 3) = 360 .If the order of the 4 numbers doesn't matter, then there are 15 different groups of 4.
I doubt it. You can get 7,676,760 different groups of 6 numbers out of a bucket of 40 numbers. No website is going to give you that much output for a single input.
Number of combinations = 45C6 = 45!/6!(45-6)! = 8,145,060
Any "cube" has 6 faces, so you could have 6 different numbers, as on dice.
6, as long as they are all different
30
There are about four different groups of crystals structures that are available in the minerals. The four have different orientations of the close-packed layers.
6 if order doesn't matter