The answer would depend on the size of the gift box.
125 of them.
Eight half inch cubes would fill a one inch cube.
The answer depends on how large the prism is.
It would take 27 cubes with sides of 2cm.
27 of them.
216 are.
2 layers would fit in the prism and each layer would have 15 cubes. Total: 30 cubes.
This is not well-worded. The smaller the cubes the more you'd need to fill a container, and the more completely they'd fill it. One large cube would not fill a round container but there might not be room for more than one.
Volume of cube = 5 cm * 5 cm * 5 cm = 125 cm3 so 125 would be needed.
288 of them.
There is no name for it. If you were looking for the answer "capacity" the question is very poorly worded.
area