Help: Volume, mass and desnity

Im doing a science experiment for school where I have to count different wast groups. I got my mass and volume but it looks wrong because the mass is so small compared to the volume. I need to work out density too. Would that just be m/v so for recyclable plastics 426/10963 and answer in g/cubic cm. Oh btw the following mass is in g and volume cubic cm

Recyclable Plastics
Mass=426 Volume=10,963

Non-recyclable plastics
Mass=677.5 Volume=8868

Metals
Mass=323 Volume=4424

Paper
Mass=25 Volume=270

Carboard
Mass=224 Volume=9818

Glass
Mass=1000 Volume=10,227

Density = (mass / volume) = 426/10,963, = 0.03886g/cc. Yes, this looks suspicious, you must have something wrong.
Density = (mass / volume) = 677.5/8868, = 0.078g/cc. Definitely could be suspicious also.
How did you arrive at the figures?

Your figures look reasonable.
I assume the recyclable plastics consist of empty
beverage containers which are essentially hollow shells.
The same is true for steel cans and glass bottles.

One of the motivations for recycling is the huge volume of
empty space occupied by discarded containers.
Glass and plastics are crushed and shredded for densities
of 2.6g/cc, and .9g/cc respectively.

Volume is bad!