Answer:
640
Explanation:
20*5=100
4*12=48
6*5=30
4*4=16
12*6=72
20*6=120
cause these are rectangles you only need 3 side
but also don't forget that little section that they are connected
100+100+48+48+36+36+16+16+72+72+120+120=784
calculate the connected area
72+72=144
s0...
784-144=640