3000 lbs = 1360 kg, for people like me who are finding mental maths a little difficult at this time in the morning.
/2 = 1500 .1 = 150 = 1500 - 150 = 1350kg
Google's result: 1360.777kg
10% is small enough that it does not matter for these types of informal conversational scenarios, and in cases where it does, do a proper conversion.
An average 1 km3 cloud has 500000 kg of water droplets.
The Sun is another interesting (size * density) example. The Sun's "power per unit volume" is only about the same as a compost pile. But because it's so large, this is enough to keep it glowing brightly.