## Variations theory

**Variations** is to group elements, when it matters the order, we do not take all the items and these can be repeated or not. Thus the variations may be:

__– Variations without repetition of n elements__

It is called common variations of m elements taken from n in n (m = n) to different groups consisting of n elements, choosing them among the m elements that we have, so that:

– All the elements are not included.

– The order matters.

– The ítems are not repeated.

Therefore, a variation will be considered distinct from another if they differ in some element or if they are located in a different order.

__– Variations with repetition of n elements__

It is called variations with repetition of m elements taken from n in n to the different groups formed by n elements such as:

– All the elements are not included if m is greater tan n. All the elements are included if m=n.

– The order matters.

– The ítems are repeated.

In this case, a variation will be considered distinct from another if they differ in any of the elements or if they are located in different order.