\begin{definition}[Definition:Complex Number/Definition 2/Addition]
Let $\tuple {x_1, y_1}$ and $\tuple {x_2, y_2}$ be complex numbers.
Then $\tuple {x_1, y_1} + \tuple {x_2, y_2}$ is defined as:
:$\tuple {x_1, y_1} + \tuple {x_2, y_2}:= \tuple {x_1 + x_2, y_1 + y_2}$
\end{definition}