Answer:
Step-by-step explanation:
The house is split into two cubes: The main house, and the "chimney"
The volume of the main part of the house is 20*20*21 mm=8,400mm cubed
The chimney's volume = 11*5*2mm = 110 mm cubed
Now, you just need to add them up.
8,400+110 mm cubed = 8,510 mm cubed
