Write a single iterated integral of a continuous function $f$ over the following region.
The region bounded by the triangle with vertices $(0,0),(24,0)$, and $(12,12)$.

Step 1 ：Determine the limits of integration for the $x$ and $y$ variables over the triangular region

Step 2 ：Split the region into two parts: the first part bounded by $y=0$, $y=x$, and $x=12$, and the second part bounded by $y=0$, $y=24-x$, and $x=12$

Step 3 ：For the first part, set the limits of integration for $y$ from $0$ to $x$, and for $x$ from $0$ to $12$

Step 4 ：For the second part, set the limits of integration for $y$ from $0$ to $24-x$, and for $x$ from $12$ to $24$

Step 5 ：Write the single iterated integral for the entire region as the sum of the integrals for the two parts: ${\int }_0^{12}{\int }_0^{x}f(x,y)dydx+{\int }_{12}^{24}{\int }_0^{24-x}f(x,y)dydx$

Step 6 ：$\boxed{{\displaystyle {\int }_0^{12}{\int }_0^{x}f(x,y)dydx+{\int }_{12}^{24}{\int }_0^{24-x}f(x,y)dydx}}$