Description Sangwigwon Yeonsan 960 approaches number and calculation learning—the starting point of mathematics and an essential tool across all areas of the subject—with a fresh philosophy and methodology. Through task-solving calculation problems combined with a variety of situations, processes, and approaches, this series not only completes children's calculation skills but also builds higher-level mathematical thinking. Sangwigwon Yeonsan 960 will be a great help for children who find simple, repetitive calculation practice boring or tedious; children who need creative-thinking calculation practice beyond the basics; children working on advanced application problems tied to the school curriculum; children who need to think through math rather than mechanically solve problems; children who want to build a solid foundation rather than rush into excessive advanced learning; children preparing step by step from an early grade for gifted education programs, math olympiads, or specialized secondary schools; and indeed all children who love math and want to excel at it. [Book Composition] 6 books at the P level, 4 books each at 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, Applying Addition and Subtraction [Recommended Grade] An essential critical-thinking calculation workbook for top-performing 1st grade elementary school students Table of Contents A1: 241–300, Numbers up to 100 Issue 1: Numbers up to 9 Issue 2: Numbers up to 50 Issue 3: Numbers up to 100 (1) Issue 4: Numbers up to 100 (2) Answer Key