This document discusses arithmetic sequences, which are sequences where the difference between successive terms is always the same number called the common difference. It provides examples of arithmetic sequences and formulas for finding individual terms and the sum of terms. Key formulas introduced are the term generating formula an = a + (n-1)d, where a is the first term and d is the common difference, and the formula for the sum of n terms S = (n/2)(a1 + aN), where a1 is the first term and aN is the last term.