im trying to help my younger brother with his homework, but im pretty much stuck at this question. how should i go about it?

Answer:
4000 cm^3
Step-by-step explanation:
Step one:
We are given that the original length and width of the cube is 20cm
if the cut part is 10cm
hence the dimension of the cut part is
lenght = 20cm
Width= 20cm
Hieght= 10cm
Step two:
the volume of the cut part will be
Volume= 20*20*10
Volume= 4000 cm^3
This is a hard one, but i hope this helps out!