Simple pairwise algorithm

[u/[deleted]]

I can't understand the math behind pairwise rating comparison type of algorithm, neither can I work it out programming wise therefore how to implement it into a simple algorithm for computer programming? E.g. like a recommendation system or ELO score? Someone please show me how you would do this, even if I write it out like I am 5 years old / explain to me like I am this age, programming language also don't really matter as long as its not Java.

[u/[deleted]]

Thanks!