20 1 1 why is the national high school mathematics league divided into AB volumes?
The topic of ab paper is similar in difficulty, and the reason why it is divided is to prevent the test questions from being leaked before the exam. For example, before the exam, the answers in a paper are everywhere, so the exam will lose its meaning. Once the person in charge knows, he will use B paper with almost different questions and different answers to ensure the smooth progress of the exam.