Description Sangwigwon Yeonsan 960 approaches number and arithmetic learning—the starting point of math and an essential tool across all areas of the subject—with a new philosophy and methodology. Through task-based arithmetic problems combined with a variety of situations, processes, and approaches, this series not only completes children's computational skills but also builds advanced mathematical thinking abilities. Sangwigwon Yeonsan 960 will be a great support for children who find simple repetitive arithmetic practice boring or tedious, children who need creative-thinking arithmetic practice beyond the basics, children working on advanced application of school curriculum, children who need to think through math rather than solve problems mechanically, children who want to build solid fundamentals rather than rush into excessive advanced study, children preparing step by step from an early grade for gifted education programs, olympiads, or specialized schools, and indeed any child who loves math and wants to excel at it. [Book Composition] 6 books in the P level, 4 books each in levels A through D, 22 books in total A1: 241-300 Numbers up to 100 A2: 301-360 Addition A3: 361-420 Subtraction A4: 421-480 Application of Addition and Subtraction [Recommended Grade] Essential critical-thinking arithmetic workbook for top-performing 1st grade elementary students Table of Contents A2 301-360 Addition Issue 1: Addition up to 10 Issue 2: Two-Digit Addition Without Carrying (1) Issue 3: Two-Digit Addition Without Carrying (2) Issue 4: One-Digit Addition With Carrying Answer Key Included