The post linked discusses the basics of set theory. Part 2, which goes into how set theory is used for constructing numbers like the square root of 2, is here:

The post linked discusses the basics of set theory. Part 2, which goes into how set theory is used for constructing numbers like the square root of 2, is here: https://vinaybhaip.com/blog/2020/11/22/sets-to-numbers https://vinaybhaip.com/blog/2020/11/22/sets-to-numbers.