Walk into the Keystone Algebra I exam knowing the score is yours to take. This complete study guide gives Pennsylvania students a clear, plain-language review of every module the exam covers, plus 600 original practice questions, each with a full written explanation. Every explanation shows why the right answer is right and why each wrong answer is a common algebra mistake. Covers operations and exponents, linear equations and inequalities, functions, systems, polynomials and factoring, and data analysis and probability, with clear worked diagrams and graphs. Includes 2 full-length practice exams with complete answer keys. An independent study aid, not affiliated with or endorsed by the Pennsylvania Department of Education.