$\left(\begin{matrix}2\\2\end{matrix}\right)$

$\left(\begin{matrix}3\\2\end{matrix}\right)$

$\left(\begin{matrix}4\\2\end{matrix}\right)$

$\left(\begin{matrix}5\\2\end{matrix}\right)$

$\left(\begin{matrix}6\\2\end{matrix}\right)$

$\left(\begin{matrix}7\\2\end{matrix}\right)$

$\left(\begin{matrix}8\\2\end{matrix}\right)$

$\left(\begin{matrix}9\\3\end{matrix}\right)$

$+$

$+$

$+$

$+$

$+$

$+$

$=$

In general, for a triangle as above with $N$ rows, the total will be $\left(\begin{matrix}N+2\\3\end{matrix}\right)$.