I am a graduate of 120. We talked about it at the beginning and later. The reason is this: compulsory 3 is the content of algorithm and probability, which is a new content in the outline. There is little chance of the college entrance examination. In some provinces, even if it is optional content, many teachers are willing to talk about important content first, which has little to do with mathematics. We can talk later. In reality, there are the following situations:

1。 Senior two, individual classes change teachers. In order to make a good first impression on students and gain everyone's trust as soon as possible, new teachers usually talk about compulsory 4 or other difficult content first. Compulsory 3 is all algorithms and so on, which can't reflect the strength of teachers.

2。 Compulsory 3 is the content of algorithm and probability, and it is a new content in the outline. The college entrance examination is unlikely to give questions, and some non-provincial key schools may not regard it as their own reading content.

3。 The probability of compulsory three is reproduced and extended in the elective book. In order to ensure the consistency of knowledge, some teachers put the probability in the elective book and the probability of compulsory three together.

Many teachers are willing to talk about important content first, and non-key content that has little to do with mathematics can be talked about later.

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