20 15 20 16 Zhejiang science mathematics is difficult. The reason is the difficulty setting of the exam and the way of setting the questions.

1. Test difficulty setting: the test difficulty is set by the questioner. If the questioner pays too much attention to the depth and difficulty of knowledge points, it will easily lead to the difficulty of the whole exam.

2. Questioning methods: Questioning methods will also affect the difficulty of the exam. If the questioner uses some relatively novel or unusual ways to write the questions, it may make it difficult for candidates to understand or deal with them.