The number of combinations is as follows where number n and number_chosen k. To calculate combinations we will use the formula n C r n. It is interesting to also note.
We want to have as many sets of 2 as possible.
In fact if you know the number of combinations you can easily calculate the number of permutations. Pnr Cnr r. Keep visiting BYJUS to get more such. If the elements can repeat in the combination the formula is.