Description Sangwigwon Yeonsan 960 approaches number and arithmetic learning—the starting point of mathematics and an essential tool across all areas of math—with a new philosophy and methodology. Through task-based arithmetic problems combined with diverse situations, processes, and approaches, this series not only helps children master computational skills but also builds higher-level mathematical thinking. 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 a solid foundation rather than rush into excessive advanced learning, children preparing step by step from an early age for gifted education programs, olympiads, or specialized middle/high schools, and indeed any child who loves math and wants to excel at it. Table of Contents 201~240 Addition and Subtraction with Carrying/Borrowing Unit 1: Addition Unit 2: Subtraction Unit 3: Addition and Subtraction, Calculations with Three Numbers Unit 4: Problem-Solving Arithmetic Answer Key