An arithmetic sequence is a list of numbers in which each number is obtained by adding a fixed amount, called the common difference, to the previous number. For example, in the sequence 2, 5, 8, 11, the common difference is 3, since each number increases by 3. This pattern continues indefinitely, making it easy to predict future numbers in the sequence. Arithmetic sequences are useful in various real-life situations, such as calculating savings over time or determining the total cost of items bought in bulk. Understanding this concept can help in solving problems related to math, finance, and even science.