The document discusses arithmetic sequences and provides examples and explanations. It defines an arithmetic sequence as a sequence where each term is obtained by adding a constant to the preceding term. It explains that the common difference is this constant value, which can be found by subtracting consecutive terms. The formula for the nth term of an arithmetic sequence is given as an = a1 + (n-1)d, where a1 is the first term, n is the term number, and d is the common difference. Several examples are worked out applying this formula to find specific terms of given arithmetic sequences.