20 12 Although most people say it's simple, they didn't do well in the exam. Although some problems are simple, some problems have loopholes. The overall difficulty is moderate.

So the math problem of 20 13 will be as difficult as that of 20 12, but some will not be too easy, and some will be too simple and stable as a whole. Or slightly more difficult than 20 12.

At least the difficulty will not be ups and downs!

Personally, it is similar to 09, 10.