An Arithmetic Progression (AP) is a sequence of numbers in which the difference between consecutive terms is constant. This difference is known as the common difference. For example, in the sequence 2, 4, 6, 8, the common difference is 2. APs are widely used in various fields, including finance and computer science, to model linear relationships. The formula for the nth term of an AP can be expressed as: a_n = a_1 + (n - 1)d, where a_1 is the first term, d is the common difference, and n is the term number. Understanding APs is fundamental in mathematics, as they lay the groundwork for more complex concepts like geometric progressions and series.