Why are the pairs of numbers written in primary schools arranged in front of each other, while the coordinates of middle schools are written in front of the X axis and behind the Y axis? Don't they all indicate the positional relationship? Why not unify them? Mathematical knowledge should be learned from the shallow to the deep,

Pupils are not as easy to accept as middle school students.

So along the way, you will find that there is a contradiction between what you learned before and what you learned later.

It seems contradictory, but it is only better understood by people at that time.

For example, do you need to explain to primary school students that the harmony of Yongzheng is called harmony instead of harmony?

This is a truth.

Ask me if you don't understand, and I'll be more specific. I wish you progress in your study!