//@ In the course of the next few parts, we are going to build a data-structure for computations
//@ with *big* numbers. We would like to not have an upper bound to how large these numbers can
//@ get, with the memory of the machine being the only limit.
+//@
//@ We start by deciding how to represent such big numbers. One possibility here is to use a vector
//@ "digits" of the number. This is like "1337" being a vector of four digits (1, 3, 3, 7), except
//@ that we will use `u64` as type of our digits, meaning we have 2^64 individual digits. Now we