Arithmetic Progression

An arithmetic progression is the simplest and most intuitive kind of sequence — one where you move from one term to the next by adding a fixed, constant number. That constant is called the common difference, often denoted by $d$, and it is the heartbeat of the entire progression. Once you know the first term $a$ and this common difference $d$, the whole sequence unfolds predictably: $a, a+d, a+2d, a+3d, \dots$. This predictable structure makes arithmetic progressions the perfect starting point for understanding how patterns in numbers can b …