This course is intended for mastery learning of prerequisite content for Geometry, Algebra 1, and Algebra 2. Students will start with a basic review of operations, numerical skills, mathematical notation, and number theory. Units on parts of a whole and algebra basics follow. After a brief exposition of data display, the main emphasis of the second semester is writing expressions and solving equations, in preparation for Algebra 1. The course finishes with discussion of properties of real numbers and graphical representations of algebraic expressions. Every topic in the course is taught until every student has mastered it.