Why is it easy to use the calculation method of primary school in the current mathematics textbook, and it takes at least one piece of paper to solve a problem in junior high school?
Because junior high school textbooks tell you the ideas and methods to solve this problem, solving this problem is not the whole purpose, because when you continue to study, you will find that not all problems are easy to use the calculation methods of primary school. It takes at least one piece of paper to solve a problem by solving problems in junior high school. So the purpose now is to master this method, which will definitely be used in the future!