Understand Volume as Cubic Units Practice Test

A solid is built from unit cubes (each cube is $1$ cubic unit). The cubes fill the space completely with no gaps or overlaps.

The solid has:

• 3 cubes on the bottom layer
• 3 cubes on the second layer stacked directly on the bottom layer
• 3 cubes on the third layer stacked directly on the second layer

Which statement about the volume is correct? (Volume is measured in cubic units.)

A solid is built from unit cubes that fill the space completely with no gaps or overlaps. Volume is measured in cubic units.

A student says, “This solid has a volume of 14 cubic units because I counted 14 cubes on the outside.”

But the solid is actually made of:

• Bottom layer: 12 cubes arranged as a $4\times3$ rectangle.
• Top layer: 4 cubes arranged as a $2\times2$ square stacked on one corner of the bottom layer.

Which statement about the student’s reasoning is correct?