Billed amount and realized amount?

adenine

Subtract. Gross is the amount you started with. Net is the amount you have left after some was taken away. (for whatever reason) So if you gross $1000 and than pay $200 in taxes you "net"...

Volume; mass is a measure of the amount of matter, and volume is a measure of the amount of space.

Density is the mass divided by the volume.

Mass / Volume = Density