MavisGood. Diagram is very clear. The area of all the parts are correctly represented :)Just a point to clarify, why the unit "cm^2"? In the shaded area, you have also clearly shown how to get the answer using using the FOIL method.However, you have not shown how to find the answer by 'subtracting the parts'.Please add that working in this SAME post by editing the post.No need to take the picture again.
I assume that the units is cm for all measurements in the diagram , thus the units of the areas are "cm^2" . I am sorry , I forgot to include the picture of the back of the paper. I will include the picture instead.