A subset is a collection of elements that are all contained within a larger set. In the context of combinations and binomial coefficients, subsets play a crucial role as they represent the different groups that can be formed from a given set of items. Understanding how to identify and count subsets is essential for calculating combinations, which are often expressed using binomial coefficients, symbolized as $$\binom{n}{k}$$, representing the number of ways to choose $k$ elements from a set of $n$ elements.
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