If you want to understand the idea of calculus, you must have the mathematical basis of limit and derivative. In other words, if you can't understand the concept of limit thoroughly, you must use it skillfully; We can't have an intuitive concept of derivative model, so the premise of learning calculus is not mature enough. Because if you don't know the limit, you will never understand how great calculus is (of course, this greatness stops at linear algebra), and if you don't know the derivative, you won't understand how the real meaning of the combination of numbers and shapes is embodied in analytic geometry ... The landlord needs to have an intuitive and perceptual understanding of the limit and derivative first, and then it is appropriate to study calculus in a limited way. If you can't learn calculus at one time, it will lead to the complete abolition of mathematical concepts in middle schools in the future. ....................................................................................................................................................

PS: If you just want to have a basic understanding, recommend the famous mathematics book of the former Soviet Union: Mathematics and its Content, Method and Significance. ",and the famous mathematical science book" From One to Infinity ". These two books will make you completely shocked by mathematics.