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# Variations with repetition

Given a set A of n different elements and m a whole number, m (m<n). In how many ways can we choose m elements from A?

The answer depends on the exact conditions of choice:

When the ordering of objects matters, and an object can be chosen more than once, we are talking about variations with repetition, and the number of variations is:

nm

where n is the number of objects from which you can choose and m is the number of objects we can choose (repetitions allowed)

How many words of 2 letters can you make with 4 letters a,b,c,d?.
The subsets are the following: