Combination Calculator (nCr)

The combinations calculator helps determine the number of possible combinations from a given set of objects, typically denoted as "n choose k." In these combinations, what matters is the composition of elements, not their order. For instance, consider a scenario where there are 4 different types of envelopes available at a post office. The calculator helps answer questions like, "In how many ways can you purchase 6 envelopes?" The formula to calculate the number of combinations from n elements taken k at a time is n! / [(n - k)! * k!].