The pre-algerba section includes typical concepts such as integers, equations, factors and fractions, rational numbers, ratios, proportions, percents, inequalities, functions, graphing, right triangles, and two-dimensional figures.
In its most general form, algebra is the study of mathematical symbols and the rules for manipulating these symbols; it is a unifying thread of almost all of mathematics. It includes everything from elementary equation solving to the study of abstractions such as groups, rings, and fields.
According to Google: the branch of mathematics concerned with the properties and relations of points, lines, surfaces, solids, and higher dimensional analogs.