I recommend reading Ancient and Modern Mathematical Thoughts, written by an American. If you like math, you will be attracted and shocked by this book. You can see the content from the title, haha. You can see all kinds of mathematical ideas through the ages. The author is engaged in mathematics teaching, which is very suitable for students to read. If you are a freshman, you can look at it without looking at the high number.

There is also a book written by the Soviets, Content, Method and Significance of Mathematics, which talks about the thinking methods of different branches of mathematics. You can look at what you have learned so far. It is also an easy-to-understand book, but it is worthy of serious understanding.

These two books are systematic and can help you to establish a general concept of mathematics. They are also recognized as masterpieces of mathematics and will not lead you astray. There are many kinds of popular mathematics books on the market, but most of them are business books. If you are interested in mathematics, I strongly recommend these two books. Come on!