Inverse Completion of Natural Numbers
Theorem
There exists an inverse completion of the natural numbers under addition.
Proof
The set of natural numbers under addition can be denoted $\left ({\N, +}\right)$.
From Natural Numbers under Addition form Commutative Monoid, the algebraic structure $\left ({\N, +}\right)$ is a commutative monoid.
Therefore by definition of commutative monoid, $\left ({\N, +}\right)$ is a commutative semigroup.
From Natural Number Addition is Cancellable, all of the elements of $\left ({\N, +}\right)$ are cancellable.
The result follows from the Inverse Completion Theorem.
$\blacksquare$