Finding volume of a grouped object

Hi, I am trying to get Sketchup to tell me the volume of this table model. It will tell me the volume of the tabletop, which I had made into a solid group, and it will tell me the volume of the legs which I made into components (it says 0.0 m^3 but I know that I just need to adjust the number of decimal points). The issue is when I want the volume of the whole thing; I tried making all five pieces into a group but it tells me it isn’t a solid(?) or at least when I turn on solid inspector it says I have five nested objects.

On the web version of sketchup for schools there does not appear to be an “ungroup” option so I couldn’t try different grouping configurations.

I am told that I might want to eliminate internal faces but I can’t see how to do that; viewing this in x-ray mode still doesn’t allow me to select the internal face.

I tried exploding it but I am not entirely sure what that even does.

Anyhow I attached the model. The whole reason I was doing this was so students could get the model volumes and do density / mass calculations.

Thanks! density exercise table II .skp (264.5 KB)

Use Solid Tools > Outer Shell

Don’t forget to make a copy before!

Thanks, that helped a lot. Seems to have worked!