1. Definition of an Arithmetic Series2. Sum of First \(n\) Terms of an AP2.1. Using the Pairing Method2.2. Using the nth Term Formula3. Formulas for \(S_n\)3.1. Formula \(S_n = \dfrac{n}{2}(a + l)\)3.2. Formula \(S_n = \dfrac{n}{2}[2a + (n-1)d]\)4. Applications of AP Sum4.1. Finding Number of Terms4.2. Finding Common Difference or First Term5. Examples5.1. Simple AP Sum Examples5.2. Real-Life Applications of AP Series