Answer:
1000
Explanation:
I guess, something went wrong with the text up there.
I assume it should say 2cm×2cm×2cm cubes. right ? because a cube has 3 dimensions, not just 2.
otherwise an infinitely large number of "just squares" would fit into the box ...
so, the box is
1m×20cm×4cm = 100cm×20cm×4cm = 8000 cm³
a single cube would be
2cm×2cm×2cm = 8 cm³
therefore,
8000 / 8 = 1000 cubes can be packed into that box, since the dimensions of the box in relation to the dimensions of the cubes do not force to have some empty left over space. the box can be packed tightly.