Question 5
As shown in the diagram below, the area of rectangle $ABCD$ is $408\ \mathrm{cm}^2$. Points $M$ and $N$ lie on side $CD$, such that $DN:NM:MC=2:3:1$. Points $P$ and $Q$ are the midpoints of sides $BC$ and $AD$, respectively. If the areas of the four shaded regions are $a$, $b$, $c$ and $d\ \mathrm{cm}^2$, respectively, what is the value of $(a+d)-(b+c)$?
