"What's important for understanding arithmetic is to 'visualize' abstract concepts using diagrams and concrete examples." Hello. I've taught mathematics in junior high school for 13 years and arithmetic in elementary school for 2 years, supporting children's learning for 15 years. What I've come to realize is that there are reasons for each setback in arithmetic and mathematics. Sometimes it's due to an insufficient understanding of the basics, sometimes the study method isn't right, or even if the calculation method is memorized, the meaning isn't understood. When I observe children struggling with mathematics in junior high school, the cause is often that the content learned in the 5th and 6th grades of elementary school hasn't been sufficiently mastered. Learning arithmetic is cumulative. Carefully building the foundation, like the roots and trunk of a tree, supports subsequent learning of junior high school mathematics. The reason arithmetic becomes more difficult as students progress through the grades is due to "abstraction." The fact that "two apples and three apples add up to five," which was learned in the first grade of elementary school, was easily visible. But what about "1/2 + 1/3"? What about "2x + 6 = 18"? It becomes quite difficult to visualize those scenarios, doesn't it? I aim to create lessons where children can understand and accept concepts that are difficult to grasp through words and equations alone, by "visualizing" them with diagrams and concrete objects. Not every child will benefit from the same teaching or learning method. However, the key to mastering arithmetic is to "visualize" what was previously invisible. Let's transform "I don't understand" into "I understand" by "visualizing" the previously invisible mechanisms of arithmetic one by one.