Side Topic:

If you have selections, with replacement, from a set of distinct objects (E.G. 6 sides of a die), then the size of the Sample Space is . So the total amount of possible outcomes for rolling a dice 3 times is . (Technically if you get a side of the die, you replace it again for the next roll).

Permutations: That, but without replacement.

Formal Definition:

Any ordered sequence of objects taken without replacement from a set of distinct objects is called a permutation of size of the objects. The number of permutations of size that can be constructed from the objects is denoted by .

OR

Note: The order of which you’re dealt matters, making Permutations grow so quickly. So, in dice, a and a are different.