Let $\mathbb{Z}$ be the D367: Set of integers.
Let $\pm$ be the D637: Natural number addition operation.
The integer addition operation is the D554: Binary operation \begin{equation} + : \mathbb{Z} \times \mathbb{Z} \to \mathbb{Z}, \quad [(a, b)] + [(c, d)] = [(a \pm c, b \pm d)] \end{equation}