About "Competitive Mathematics for Gifted Students" This series provides practice materials and short theory reminders for students who aim to excel at problem solving. Material is introduced in a structured manner: each new concept is followed by a problem set that explores the content in detail. Each book ends with a problem set that reviews both concepts presented in the current volume and related topics from previous volumes. The series forms a learning continuum that explores strategies specific to competitive mathematics in depth and breadth. Full solutions explain both reasoning and execution. Often, several solutions are contrasted. The problem selection emphasizes comprehension, critical thinking, observation, and avoiding repetitive and mechanical procedures. Ready to participate in a math competition such as AMC-8, AMC-10, Math Kangaroo in USA, Math Leagues, USAMTS, or AIME? This series will open the doors to consistent performance. About Level 3 This level of the series is designed for students who can solve linear equations, are fluent with fractions, and can factor into primes. The problem sets are designed to strengthen specific areas where we know students have difficulty on AMC-8 and AMC-10. The level 3 books are a strong preparation for AMC-8 and a partial preparation for AMC-10 and AIME. Level 3 consists of: Word Problems (volume 9), Arithmetic and Number Theory (volume 10), Operations and Algebra (volume 11), Geometry (volume 12), and Combinatorics (volume 13). On the contest list for this level: MATHCOUNTS, Math Kangaroo levels 5-6 and 7-8, MOEMS-M, Purple Comet, AMC-8, AMC-10. Their complexity makes these problem sets useful for preparing the AIME in the long run. About Volume 13 - Combinatorics and Probability This workbook presents a variety of problems that explore the most basic discrete counting techniques: permutations and combinations. The topics included are competition specific.