> The main operation, addition, is completely hidden magic
the main operation is reduction which is fairly basic computer science and taught in any non-BS curriculum - https://en.wikipedia.org/wiki/Reduction_operator (or https://en.wikipedia.org/wiki/Fold_(higher-order_function) which is the standard way to introduce this concept ; check in particular the table showcasing all the implementations in various languages). The standard reduction for a set of numbers to a number that is likely going to be the very first example in your textbook is addition.
the main operation is reduction which is fairly basic computer science and taught in any non-BS curriculum - https://en.wikipedia.org/wiki/Reduction_operator (or https://en.wikipedia.org/wiki/Fold_(higher-order_function) which is the standard way to introduce this concept ; check in particular the table showcasing all the implementations in various languages). The standard reduction for a set of numbers to a number that is likely going to be the very first example in your textbook is addition.