IMAS 2012 — Upper Primary Grades 5–6 — Round 1 Question 4

The diagram to the right shows two squares AMND and PQRS inside a rectangle ABCD. The areas of the two squares are $ 16 \, cm^2 $ and $ 4 \, cm^2 $ respectively. What is the sum of area of the shaded regions in $ cm^2 $?