Description: Sangwigwon Yeonsan 960 approaches number and calculation learning—the starting point of math and an essential tool across all areas of mathematics—with a fresh philosophy and methodology. Through task-solving calculation problems combined with a variety of situations, processes, and formats, this workbook not only helps children master calculation skills but also builds higher-level mathematical thinking. Sangwigwon Yeonsan 960 will be a great support for children who get bored or tired of simple repetitive calculation practice, children who need creative-thinking calculation practice beyond the basics, children working on advanced curriculum applications, children who need to think through problems rather than solve them mechanically, children who want to build a solid foundation rather than rush into excessive advance learning, children preparing step by step from an early grade for gifted education programs, olympiads, or specialized schools, and any child who loves math and wants to excel at it. [Workbook Composition] 6 books in the P level, 4 books each in levels A–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 thinking-skills calculation workbook for top-performing 1st grade elementary students Table of Contents A4 (421–480): Applying Addition and Subtraction - Issue 1: Applying Addition and Subtraction Without Carrying - Issue 2: Calculating Three Numbers Without Carrying - Issue 3: Applying Addition and Subtraction With Carrying - Issue 4: Calculating Three Numbers With Carrying - Answer Key