1. Algebra is a branch of mathematics that deals with symbols and the rules for manipulating those symbols. 2. It is a unifying thread of almost all mathematics and includes everything from solving elementary equations to studying abstractions such as groups, rings, and fields. 3. In algebra, letters (called variables) represent numbers in formulas and equations. 4. For example, in the equation $x + 2 = 5$, $x$ is a variable representing an unknown number. 5. The goal is often to find the value of the variable that makes the equation true. 6. Algebra helps us solve problems by expressing relationships and patterns in a general way. 7. It is foundational for advanced math, science, engineering, and many real-world applications.