What materials to study mathematics from scratch?

Question

Books

I decided to try to study mathematics on my own. Googled, many advised the book "What is Mathematics". Started reading. The first theme, progressions. And right away, as it is not very accessible, everything is explained. Written explanation on half a page, most of the explanation is just a formula. There are proofs with the help of mathematical induction, but I didn’t understand why everything was like that ...
In general, advise a book or some kind of course with practice so that you can independently, if you can, so to speak, enter mathematics without much knowledge in mathematics before.
Before that, I studied mathematics at school, then at college on a technical specialty, rather complicated things were studied. Then everything was fine, always 4-5 in math disciplines. And now it's all gone. Actually, I don't remember anything.