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Math.

1. How to Prove It: A Structured Approach, Velleman (perfectly prepares for reading of pretty much any math book)

2. Higher Algebra and before that Elementary Algebra, Hall (just some intro stuff; general public license, can be freely downloaded from archive.org)

Another book along the same vein is Introduction to Logic, Sets , and Relations by Nancy Rodgers is a beautifully written book.

I made a mistake ,its learning to reason using logic, sets and relations.