First you have to find the area of the whole shape, even around the places that aren't filled in. The you find the area of the places that aren't part of the shape and subtract those from the area of the whole shape.
35)
20×18=360
10×5= 50
360-50=310
Therefore, the area is 310 m^3
36)
6×5=30
2×1=2
3×3=9
9+2=11
30-11=19
Therefore, the area is 19 yd^3
37)
6×6=36
2×2×3=12
36-12=24
The area of this shape is 24 cm^3
38)
8×12=96
4×4=16
96-16=80
A=80 in^3