In fact, a lot of knowledge in primary schools has the shadow of advanced mathematics or very advanced mathematics knowledge. I'm a freshman in high school, and I still remember that there was a math wide angle in primary school to talk about this problem:

1/2+ 1/4+ 1/8+ 1/ 16+ 1/32+...=?

The answer is 1.

I couldn't understand it at that time. Now I have learned physics olympiad, talked about calculus, and have the idea of limit, and then I can understand it by looking at the topic. This is an application of extreme thought!

Another example: the wide angle of primary school mathematics also talks about permutation and combination, which is the knowledge of mathematical olympiad. Primary school also talked about prime numbers (prime numbers) and composite numbers, which are also the knowledge of mathematical olympiad. . . After learning primary school well, the knowledge in the future will be paved.